It’s been a year since Jennifer Lopez gave birth to her twins Max and Emme, and recently we have seen a lot more of her on the red carpet and at various galas looking fantastic.  What we don’t know is how she lost her post-baby weight.  She admitted to Entertainment Tonight that she gained 40 pounds while pregnant, but how on earth did she get it off?

“It did take a lot of work,” Lopez, 39, admits. “I thought it was gonna drop off easily because I had been in shape my whole life, but it wasn’t. I gained about 50 pounds with my twins, and the first 30 dropped off like that, and I was like, ‘Ha, this is gonna be so easy.’ That last 20 — that took a while.”

For the time being, that’s all we know about Jennifer’s weight loss.  But we do know she’s working on a new movie called, The Back-Up, and she has been taking the kids to the set and being the best mother she can be.

“I bring the babies to work with me. I love it,” she says. “Honestly, one of the best days of my life was the first day back working on this film — I wanted to do this film really badly — and bringing my babies with me that morning. I was like, ‘Oh my God, they’re with me, I’m making a movie, they’re here!’ It’s great having kids on set. It’s the best.”