Credit: Jason Kempin/Life Ball/Getty Images

Since giving birth to twins girls in December 2008, Rebecca Romijn admits that it hasn't been easy to shed the 60 pounds of baby weight she gained during her pregnancy.

"I'm still working on the last few pounds of baby weight," Romijn, 37, tells "I really just try to work in a half hour of some sort of workout routine every day. I try to break a sweat every day. It doesn't always happen that way, but that's the goal."

Romijn -- who wed actor Jerry O'Connell in July 2007 -- also reveals that nowadays, her workouts are more of a family affair.

"We play a lot of badminton, we go tandem bike riding, we try to keep it fun," the former Eastwick star says. "We try to do things as a couple and now as a family."

And now that daughters Charlie and Dolly are 19-months-old, Romijn jokes that the two are already starting to become little troublemakers.

"We took the girls on their first merry-go-round ride. One of them was really into it and the other wasn't having it," the actress tells Us. "We went for a surry ride with the fringe on top -- it's like a bicycle with the baby seats in the front. They were instructed to wear helmets but they kept trying to take them off. Then they discovered it was more fun to bash each other in the heads with their helmets!"