Photos of Jennifer Lopez on the Set of The Back-Up Plan in NYC the Day After Her 40th Birthday

Jennifer Heads to Work Another Year Older

Jennifer Lopez was back to work on The Back-Up Plan in NYC earlier today after a late one last night — the cast and crew of her film celebrated her 40th birthday with a big bash on set. Marc Anthony was there to cut a cake that featured J Lo's photo, which is a party trend that seems to be all the rage for celebs these days. Just because Jennifer has another year under her belt doesn't mean she's slowing down, as she's soon to launch a new perfume designed reflect her maturity.