Her seven-month-old “body gallery," as she calls her 3,000-square-foot space, also offers daily $35 group classes, which she herself teaches on the rare Saturdays she is not with a client on a set. (She drops casual references to nondisclosure agreements and says she only names clients already outed by paparazzi.)

She is at work on a DVD to be released next month, a book to be published by Penguin and a line of exercise clothing — and the 2013 opening of a West Hollywood outpost.

If it all sounds a little intense, Ms. De La Rue (not a stage name) and her fitness philosophy are anything but.

“It’s not about doing the steps perfectly — it’s just about keeping moving," said Ms. De La Rue, 37, a sunny Australian blonde who jokingly calls herself “bicoastal Barbie." Halfway through teaching her second class of the day on a recent Saturday, dressed in purple Nike capri pants and a neon yellow tank top, she hopscotches, shimmies and leaps with the exuberance of a high-spirited high school girl spontaneously breaking into a dance at the mall. She sprinkles her instructions with “darlings" and doles out sweaty hugs.

As for her 20 routines, which are mostly 1970s dance aerobics on speed (minus leg warmers but with Beyoncé-esque booty-shaking), “I’m not claiming I’ve invented anything new," said Ms. De La Rue, who is a classically trained ballerina. “What I am claiming is that the environment I’m creating is special: that people come in here and they feel like they’re dancing with their girlfriends."

She certainly feels that way. Her staff is “all my Australian dancer friends" and her “best friend Lucy" (Matt Damon’s wife, Luciana Barroso) is “here all the time."

Ms. De La Rue, who danced in “Promises, Promises" on Broadway in 2010, freely admits to “ripping off Jane Fonda — bless her, she was onto something." She is considerably less open about her debt to her former boss Tracy Anderson, perhaps best known as Gwyneth Paltrow’s trainer, with whom she is engaged in a bitter (super-toned) arms race.

Ms. De La Rue’s biography does not mention her apprenticeship at the House of Anderson, in whose TriBeCa lair Beyoncé and Kate Hudson have danced. She refers to it obliquely in interviews, saying that she would never charge $900 a month (the cost of membership at the gym Ms. Anderson owns with Ms. Paltrow) and that her experience taught her “to treat your staff how you want to be treated." Asked how she landed her first high-profile client, Ms. De La Rue said she “fell in with a good crowd" when she moved to New York in 2006. But when pressed, she said that Ms. Anderson (for whom she auditioned when a Broadway gig fell through the day before rehearsals were to start) provided her “initial celebrity connection."

“I worked for her for a very short period, but I try not to mention it," she said. “I wish her love. The world’s big enough for both of us. It’s just exercise."

Ms. Anderson seems not to agree. This spring, citing Ms. Anderson’s “proprietary research," her spokeswoman wrote to a fitness news Web site, objecting to a reference to Ms. De La Rue, who worked for the company for “under a year," as the “the next Tracy Anderson." The spokeswoman also objected to the Web site’s placement of a hyperlink to an article about Ms. De La Rue beneath text about Ms. Anderson.

Ms. Anderson initially agreed through a spokeswoman to be interviewed for this article, but minutes before released a statement instead that read, in part: “I worry about the results of the client who is not benefiting directly from the 13 years of research and development it has taken me to perfect this method, especially if my name is being used in some tangential way."

But Ms. De La Rue’s results are almost literally what built her studio. One high-profile client who said she could not even look at herself in the mirror, shrank three dress sizes and told Ms. De La Rue the workout had been “life-changing." She also offered to be her silent business partner so Ms. De La Rue could “share it with as many women as possible." Ms. De La Rue declined to identify her.

Grace Hightower De Niro, the wife of Robert De Niro, who dropped three sizes and dances with Ms. De La Rue, whom she calls Simmy, five days a week, said: “She will just look at me and know I had a glass of Champagne or that I ate too late and I’m sluggish. She picks up nuances that most trainers don’t."

The rest of Ms. De La Rue’s Newton-sneaker-wearing disciples (she herself has the ultralightweight shoes in every color) are also unusually evangelical and supportive, even by cult-happy fitness-world standards. Ms. De La Rue wears a tiny gold hamza charm for protection made for her by the jewelry designer Jennifer Fisher, a client.

The interior designer Michelle Gerson (who called the workout “addictive" and said that every woman she sees there is “tighter and leaner") designed the studio’s Lucite and black faux-snakeskin benches. On the slate-gray walls hang sexy portraits of Ms. De La Rue and her sinewy staff members, all snapped by Zoe Buckman, a client who is married to the actor David Schwimmer.

“I like to keep it in the family," said Ms. De La Rue, who recently moved from the Upper West Side to an apartment four blocks from “my baby" (her studio), for which she personally chose “every lick of paint, every faucet, every fixture."

Then there is Ms. Bullock. When photographers camped outside the studio during a workout in December, Ms. De La Rue recalled that the actress offered to sell “myself for you." Ms. Bullock then swapped her sweaty top for a cherry-colored Body by Simone tank, left her coat unbuttoned and lingered outside posing instead of dashing into a waiting car. “And it was the greatest thing anyone could have ever done for me," Ms. De La Rue said.

Late on a Friday afternoon, the spa-like studio — gray and black, with red accents and pewter-and-glass chandeliers — is silent except for the constant buzz of Ms. De La Rue’s iPhone. “I’m on too many girlfriend group texts," she said cheerfully. The phone at the front desk rings and Ms. De La Rue wavers (“Should I answer it?") before hurtling herself across the room to do so. “You’re only as good as your last gig," she said firmly.

Returning to her spot on the bench, she bounced lightly, uncrossing and recrossing her legs in midair, then clasped her hands, and closed her eyes briefly. “Onstage, when you audition, you’re always having to be someone else," she said. “You’re like ‘Love me, love me, please pick me to be this character.’ But with the business, for the first time ever I’ve just been myself, and it’s worked."

The Aussie (who was born in England) opened her personal studio in November of 2011 and is quickly taking over the dance fitness world. "At some point in their lives every woman has danced, or wanted to dance," she says of the cult workout movement. But her studio is more than just a way to get in shape for the new year, it's a place to hang with your girlfriends and let loose. "I always say, leave your ego at the door. I don’t care if you don’t get the step right. Just keep moving!"

Harper’s Bazaar: How did you get into fitness?

Simone De La Rue: I danced all my life and accidentally fell into fitness. I trained in classical ballet from the age of 3 and worked professionally for 16 years — I did the West End in London and Broadway here in New York. And it happens that one of the shows I was supposed to be doing was canceled two days before we were supposed to start rehearsals. And that was supposed to be a year-long contract. I had been working in fitness on the side at the time and it also happened to be the start of everyone’s obsession with wanting to have a dancer's body — it was The Black Swan era.

HB: So how do you get a dancer’s body?

SDLR: The typical way to get a dancers body is… dance! It’s because dance is a total body workout. You are not sitting on a bike and cycling or running or weight training. The idea is the body is long and lean and never at rest, just really burning calories. It’s fluid, liquid-like movement, and it’s continuous. I developed my technique, Body by Simone, over years of being a professional dancer. You do 8 shows a week, and it gets quite strenuous on the body and repetitive. So before a show, you have half an hour on the stage where you can warm up. And that is where I created my BBS warm up that I used over the years to protect my body from injury. I kind of combined little bits of it into what is now my signature cardio dance routines.

HB: Growing up as a professional dancer did you always find that the industry had a relatively healthy body image?

SDLR: No, it is tough, especially for me since I grew up in classical ballet. I’m lucky I never had an eating disorder. Some of my friends did. That is why I took a detour to musicals, they are a little more accepting of different shapes. I’ve got really broad shoulders and I still remember the day when I was 16 and the ballet school didn’t even let me dance, it was like being a model, they just made me stand there and turn, turn, turn, while they judged me.

HB: Can you explain the BBS method further and why it works so well.

SDLR: The classes we offer complement each other. It is basically 45 minutes to an hour of dance cardio and the other hour is just strictly toning. Obviously people don’t have 2 hours a day to work out, so we also do some classes that are 45 minute body blasts. You need at least 20 minutes of cardio a day, I think. It used to be you were supposed to do 30 minutes straight and now scientific research has said short 10 minute bursts tend to work better. So you do like 10 minutes of cardio, sculpting and arms, then more cardio. Plus, it goes faster.

HB: Any recommendations for nutrition, any hard fast rules?

SDLR: I think fitness is 80% diet, 20% exercise, which as someone in my field I should be saying 80% exercise, but it really is about what you eat. Obviously the exercise will complement that, and you will see faster results and quicker weight loss with BBS, but it really is about what you are putting into your body. I try to keep the amount of alcohol down as much as possible can. We are going to have a cafe in our studio called Hu Kitchen, and it is based on the Paleo diet, so no grain, no dairy, no gluten, hardly any sugar or starch. It's a lot of vegetables and protein. For me that is what works best — a very heavy protein diet, I don’t have many carbs at all.

HB: Any superfoods you swear by?

SDLR: I’m obsessed with kale. And I love turkey. Other than that I just try to remember my green juice.

HB: Any plans for more BBS studios?

SDLR: We are definitely going to open up this year in LA. We have also been looking at a space on the Upper East Side. For now, we have BBS-TV, which is like online streaming. It’s a monthly subscription, like Netflix, and you have access to all of the videos. We have 25 videos on there at the moment, you can do 45 minutes of dance cardio, we have 5 different options of that. There is also a trampoline workout and a jump rope cardio for people who don’t want to dance. If you have 10 minutes we have arms. There are abs, and legs, full body blast, and even a couples workout.

HB: Where do you find your instructors?

SDLR: Everyone at BBS is a professional dancer. Three of my head trainers I have known for 15 years. We worked together on musicals in Australia, and London and here.

HB: What about music and fashion, any workout faves?

SDLR: I'm obsessed with the new Florence and the Machine and Bruno Mars — in cardio you need 132 beats per minute to get the heart rate up. I’m also obsessed with Newton shoes. I call it an old man's triathlon shoe. I love them because they are so light, they don’t smell, they breathe and come in really fun colors. I’m also in the process of doing my own workout line, because I’m wearing it all day long and I think a lot of the stuff out there is quite generic and I want to make it more funky, more street.

BBS TV is library of workout videos with De La Rue, including her signature trampoline, jump rope, dance cardio, and sculpting sequences, plus videos on lifestyle tips—all of which the fitness trainer says she’ll be adding to regularly. You can stream them on your computer, iPad, or smart phone. Cost is $29 for a month.

The production quality of the videos, which varies widely in this genre, is satisfyingly glam yet approachable.

“Basically I created BBS TV for those who don’t have access to our NYC studio and clients who travel constantly. I can’t be with all of my celebrities when they travel—so this was the next best thing." De La Rue trains Anne Hathaway, Sandra Bullock, and more.

The videos will be most distressing to your downstairs neighbor when you activate the trampoline sequence.

Currently there are advanced classes for BBS regulars, and those for beginners. For those without the choreography-remembering gene, the 20-minute dance cardio for beginners includes a brilliant breakdown section where De La Rue teaches the sequences slowly. I could see boning up on this in between classes at the studio.

There are also 10-minute targeted workouts for arms and legs, and 4-minute cardio-revving blasts with a jump rope or trampoline. They’re all meant to be mixed and matched, so you can to design your own workout, “and so your body, along with your mind, won’t get bored," she says.

“We all lead busy lives, and require fast, to-the-point exercises that can be portable," says De La Rue. “Slowly we’re moving away from the old fashion DVD, and carrying workouts on our laptops and phones." If only these devices carried our running shoes and workout clothes, too. - Melisse Gelula

The brainchild of former professional dancer and celebrity trainer Simone De La Rue, the aptly-named dance cardio workout is "a fun, joyous way to work out," says De La Rue. We recommend steering clear if you have bad knees or back problems as the jumping is high-impact, but those with healthy joints will love the body-pumping music and high-energy environment. Body by Simone TV officially launches October 1, and a monthly membership fee grants unlimited access to regularly updated video segments that'll have you dancing your butt off — literally.

Anne Hathaway, Sandra Bullock and Matt Damon already work with New York-based trainer Simone De La Rue, formerly a classically-trained dancer, who has performed on Broadway and London's West End.

The 37-year-old, who is originally from Australia, says her core-strengthening sessions, which incorporate pilates, yoga and dance, have become a favourite with celebrities because they deliver 'long and lean' results.

She told MailOnline how the technique, originally developed to keep her dancer's body fit and free from injury, is successful because it varies different kinds of exercise.

'Like me, a lot of celebrities can be a bit ADHD when it comes to working out,' she explained. 'They need to be stimulated and do something different to stop getting bored.

'The body needs variety too. You constantly need to trick your muscles by introducing different types of exercise, otherwise they become lazy and you stop seeing any definition.'

Even though she works with many VIPs, Ms De La Rue encourages her celebrity clients 'to leave their egos at the door'.

She added: 'I think actors also connect with what I do because I encourage them to be creative. It’s a release.'

One of her most famous clients is Sandra Bullock, who turned to the BBS workouts after she split from husband Jesse James last year.

The trainer revealed: 'Sandy wanted to focus on her upper arms so we used wrist weights and slowly moved the arms in a move that mimics the "Port De Bras."'

However, while it’s easy to imagine a graceful, leotard-clad Sandra Bullock at the ballet barre, what about Matt Damon?

'It's quite a challenge for a big, beefy guy to come in and get used to working out without weights. But after an hour, they are exhausted,' she says.

Luckily for the Bourne Identity actor, his workouts were more action hero than Swan Lake. His workout from Ms De La Rue included a one-handed press-up called the Superman.

'We also do standard push-ups and work hard on the abs – as a lot of men do ab work incorrectly,' she said. 'Women are much more in tune with their core and are actually stronger in this area than men.'

But despite her impressive client list, she maintains that getting fit does not have to be costly.

'A lot of people sign up to expensive gyms and jump on all the machines to get their money's worth without knowing how to use them correctly,' she said.

‘Most of my clients come to me with injuries from bad training.'

And while a personal session at her new Body By Simone studio in New York would set you back $175, group sessions cost a more reasonable $35.

'You don’t have to be a millionaire to work out properly,' she added.

According to the Body by Simone website, her studio offers “One-On-One Body and Lifestyle Design." I decided to treat myself to a $35 group fitness class called “Dance Cardio" and to try out Simone’s fitness ideas for myself. (Celebrity fans include Sandra Bullock and Anne Hathaway.)

The Tuesday 9:30 a.m. “Dance Cardio" session was taught by dancer Sarah O’Gleby, and let me just say that this class kicked my booty in the best way possible. The idea is very old-school, dance-oriented cardio for an hour, but when I was done, I felt as if I had just run a marathon!

O’Gleby began her career as a dancer and has been on stage in London’s West End. Her energy was infectious and though my kicks were not that high (my cycling legs resemble the proverbial Wooden Soldier) and my timing a bit off, it was still a total blast, and I will definitely come back for another round soon.

This is a high-impact class, so you will have to make your own modifications if you have any back or knee issues. Also, if you do not have a dance background, it might seem a little confusing at first, so take your time learning the steps. The whole point of it is to have fun and feel like you are hanging out with your best girlfriends.

As I was gathering myself after class, a sprightly blonde with a perfect dancer’s body and an Australian accent came up to me and cheerfully said “Hi, Margo. I hear this was your first class. What did you think?" (It was Simone!) We chatted for a bit, and Simone told me about the studio’s fall plans, including a whole slew of new classes to be offered this month (including one that utilizes body bands that I MUST check out soon,) a West Hollywood studio opening, plus the launch of BBS TV—an online component that will offer workouts you can access from home. Score!

What was the best part of the workout? On my way home I made sure to check my Polar watch and discovered I had burned 633 calories in one hour—amazing! After the class, Simone was kind enough to answer a few questions for Fit Bottomed Girls! You know I had questions for her…

Interview With Simone De La Rue
What got you interested in opening your own studio? One of my clients had a huge transformation and lost three dress sizes. She was so delighted with her new improved body inside and out that she said to me: “We should share this with as many woman as we can." And that is how the Body by Simone studio was born.

What is one key piece of advice for looking to begin a health and exercise regimen? Don’t make excuses. Make time for yourself, however limited, but make time that’s just for you. Improved health improves your whole life across the board. And don’t give up. Rome wasn’t built in a day; it takes time to see change in your body, but persistence pays off!

How would you describe the Body by Simone studio to someone who has never heard of it before? It’s a Body Gallery! It’s an old art gallery turned into a dance studio. It’s a safe environment, where you leave your ego at the door and come in and experience the “girlfriend workout." A fun and creative way to get a kick-ass workout!