Pregnant Liv Tyler Isn't Doing "Crazy Workouts" Right Now: Inside Her Energy-Boosting Fitness Routine

Trainer David Kirsch, who also works closely with Kate Upton, spills secrets about both stars' exercise and diet regimens

Liv Tyler and Kate Upton rank right up there among the sexiest of female celebrities—and it turns out they both have a secret weapon.

Trainer David Kirsch recently dished to E! News about both stars' fitness routines, routines that obviously vary quite a bit these days since Tyler is pregnant with her second child.

With Liv, whom he's worked with for close to 20 years, including during her first pregnancy, Kirsch says that they're "not doing crazy workouts" at this time.

"It's different then training Kate Upton," he said when we caught up with him at Heidi Klum's Halloween party, "but we have a lot of fun."

"You want to move your body, and with that It puts you in a zone—a better zone," Kirsch continued. "You eat more healthily, you have more energy and it's healthier for the baby. Everything is better." With that in mind, they do "the same workouts we always do, but I dial it down a little bit because she's pregnant."

"It's still full-body," he said, "working on her arms, legs, butt and cardio."

And the 37-year-old star of The Leftovers is still stunning and statuesque in her stylish baby bump pics, so... check, check, check and check.

As for Upton's routine, Kirsch continues to pump up the volume. But all would be for naught if the actress and two-time Sports Illustrated Swimsuit Issue cover girl weren't such a compliant client.

"She is gorgeous, amazing and so sweet," the trainer gushed. "I mean, look you don't have to do anything when you look like her when god blesses you with that body. We stay away from carbs and sugars, the obvious things, and I dial it up."

Kirsch explained, "She has her routine I have given her and she is pretty good" even when he's not around. "This week she was here every day and we exercised, and next week she will be back every day, and that's how we do it. We do intense circuit training, boxing and focus on the core and butt as well. She eats a clean diet."

Hear that, ladies? Even Kate Upton has to put in the time to look quite so good. And... squat...and...crunch...