Accidentally on Purpose is a CBS Sitcom starring Jenna Elfman and Jon Foster. The show follows Billie Chase who falls pregnant after a one night stand with Zack, a much younger man who lives in his truck. Billie lets the father of her yet to be born move in with her, with hilarious results The show was cancelled after the first season. Laster from September, 2009 to April, 2010. A total of 18 episodes.