It was a special day in LA for Mila Kunis [1] on Thursday — she celebrated her 31st birthday! Mila kept things low-key by attending a prenatal yoga class [2] and, after working up a sweat, was showered with birthday wishes when she was given a bouquet of purple flowers as she walked back to her car. The actress has been having what looks like a fun pregnancy [3], adding to the already long list of reasons we think she'd be the perfect partner in crime [4]. She's not the only star expecting a new arrival this year — check out all the pregnant celebrities [5]!