Jennifer Lopez was all smiles as she proudly showed off her twin daughter Emme Thursday on the Los Angeles set of her upcoming comedy The Back-Up Plan.

Since welcoming Emme and twin brother Max in February 2007, Lopez has said the babies have quickly developed their own distinct personalities.

Emme "kind of like takes a step and stops and picks things up, and she's like, 'I don't know - maybe I'll eat this, I don't know.

Mom, can I have some of your water? Oh, forget it!'" Lopez said on The Rachael Ray Show in April. "She's really kind of indecisive, but at the same time very precise."

Emme has her moments," the star said. "She's funny because we call her Emme-tude. We're like, 'She's giving us Emme-tude!'" She doesn't do the whole knocking everything down and all that, but when she catches an attitude, wooooah! She gets that from her dad. I'm kidding - she gets it from me!"

Max "is more like the visceral boy, running, knocking things down, eating the world," said Lopez. Will Max and Emme get any sibs anytime soon? Lopez isn't ruling out anything. That's why she still is holding on to her pregnancy sweatpants. Said the actress, "Who knows if I get pregnant again? I might need them!"