Walking up the steep flight of steps to Mary Helen Bowers’ Ballet Beautiful studio in Soho is nearly as rigorous as her signature workouts themselves. It’s a wonder that Bowers, shown above and due to have her first baby in mid-December, can still propel herself up the stairs. “That’s my warm-up,” she jokes, noting that her it gets her heart pumping a bit more these days. Bowers is famously known as the ballerina who helped train Natalie Portman for her role in Black Swan, and she’s now the secret training weapon for Victoria’s Secret models Miranda Kerr, Doutzen Kroes, Lily Aldridge, and Lindsey Ellingson, who have been training this month for the upcoming Victoria’s Secret fashion show.

Since becoming pregnant, Bowers has also developed the Ballet Beautiful Prenatal video series, which mamas-to-be can stream online, along with a full library of other workouts. Focusing on flexibility and strength-training, with low-impact movements and lots of stretching, the series grew from Bowers’ experience training pregnant clients over the years as well as her own pregnancy. “I know what feels good and doesn’t feel good now, being pregnant myself. I’ve been doing lots of core work throughout, which has really helped my back. Certain ranges of motion now feel different then earlier in my pregnancy, so I’ve been able to make those adjustments in the workouts.”

With a focus on lengthening and strengthening muscles in similar ways to classical ballet, the Ballet Beautiful body, as evidenced by those gorgeous Angels on the runway, is lean and toned, with absolutely zero bulk. “My approach is always to connect to the deepest muscles, whether you’re working on your thighs or your abs, so that you really strengthen them and get the results,” she says. Working out with Bowers is a bit like excercising with a close friend–except that she’s totally kicking your ass, quietly and demurely. As a fan of the streaming video series (a total lifesaver after my daughter was born), it was interesting to get the hands-on treatment that private clients rave about. When I asked her how often I should be working out to really see results, I was relieved to hear her answer: “Three hours a week. That’s really enough to see a change in just a few weeks.” Busy moms have lots of trouble finding the time for excercise–but the glory streaming the web videos is that they can be done virtully anywhere (though your data plan might go through the roof, as I’ve learned the hard way), with short 15-minute “blast” workouts that target specific body parts, to longer 30-minute cardio and toning sessions that seriously get the job done.

Knowing that I could be only weeks away from having a Victoria’s Secret model body (ish) has been a serious motivator–I’m now working some of Bowers’ ab moves into my morning cartoon time with my daughter, and I’ve been tuning in to the streaming videos during naptime–15-30 minutes doesn’t feel like such a huge chunk of time, and I’m totally seeing the results. Am I ready to walk down the runway wearing wings and little else? Not yet. But ask me again in a few weeks.