41. Lily Allen
Lily Allen is a doting mama now, but the artist known for her sarcasm-laced pop songs wasn't always someone you'd picture to be mom of the year. She dropped out of school when she was 15, was arrested for assaulting a photographer, and insulted numerous sexy famous ladies (which she later explained as a self-esteem issue).
Some other highlights of Lily's bad girl act include: telling Elton John to "fuck off" onstage and enjoying too many cocktails at the Cannes screening of How to Lose Friends and Alienate People, which resulted in a picture of her slumped over at a table with a cigarette in her hand.