Watch a sneak peek of the new CBS show ACCIDENTALLY ON PURPOSE “Pilot” premiere episode starring Jenna Elfman and Jon Foster and airing Monday, Sept. 21 (8:30-9:00 PM, ET/PT).

Synopsis: ACCIDENTALLY ON PURPOSE “Pilot” Season Premiere – After breaking up with her commitment-phobic boyfriend, Billie has a fling with a younger guy, ends up pregnant and decides to keep the baby – and the daddy, on ACCIDENTALLY ON PURPOSE, a new comedy premiering on Monday, Sept. 21 (8:30-9:00 PM, ET/PT) on the CBS Television Network.

ACCIDENTALLY ON PURPOSE, based on the bestselling memoir by Mary F. Pols, is a comedy about a single woman, Billie, who finds herself “accidentally” pregnant after a one-night stand with a much younger guy, and decides to keep the baby…and the guy. A newspaper film critic, Billie is barely surviving a humiliating breakup with her charming boss, James, who’s still trying to resume their relationship. Pregnant, after a brief fling with her “boy toy” Zack, they make an arrangement: to live together platonically. Billie’s party girl best friend Olivia, and Abby, her conventional, younger married sister, eagerly look forward to the new addition and offer their own brands of advice and encouragement. But when Zack and his freeloading friends, including Davis, start to turn her place into a frat house, Billie isn’t sure if she’s living with a boyfriend, a roommate, or if she just has another child to raise.