Juan Sharma/Pacific Coast News; Inset: INF
06/13/2012 at 03:35 PM EDT
is working on her post-pregnancy body
Just six weeks after giving birth to daughter Maxwell Drew
, Simpson stepped out in apparent workout gear on Tuesday and made her way to an L.A. gym. The new mom has also announced she will be working with Weight Watchers
"I think anybody who's gone through a pregnancy, after they have the baby, it's like, 'I need to do something about this,' " she told PEOPLE recently.
"For me, I really want to do something that is a lifestyle, because in the past," she continued, "I've been known to yo-yo diet." – Evan Lambert