<Ul> <Li> Megan Fox as Desi, one of Debbie's employees </Li> <Li> Albert Brooks as Larry, Pete's father </Li> <Li> John Lithgow as Oliver, Debbie's 65 - year - old father </Li> <Li> Chris O'Dowd as Ronnie, one of Pete's employees </Li> <Li> Melissa McCarthy as Catherine </Li> <Li> Ryan Lee as Joseph </Li> <Li> Lena Dunham as Cat, one of Pete's employees </Li> <Li> Robert Smigel as Barry, Pete's friend </Li> <Li> Annie Mumolo as Barb, Debbie's friend </Li> <Li> Joanne Baron as Mrs. Laviati </Li> <Li> Ava Sambora as Wendy, Sadie's best friend </Li> <Li> Michael Ian Black as Bank Consultant </Li> <Li> Billie Joe Armstrong as himself </Li> <Li> Graham Parker as himself </Li> <Li> Ryan Adams as himself </Li> <Li> Tom Freund as himself </Li> <Li> Bob Andrews as himself </Li> <Li> Brinsley Schwarz as himself </Li> <Li> Martin Belmont as himself </Li> <Li> Andrew Bodnar as himself </Li> <Li> Steve Goulding as himself </Li> </Ul> <Li> Megan Fox as Desi, one of Debbie's employees </Li> <Li> Albert Brooks as Larry, Pete's father </Li> <Li> John Lithgow as Oliver, Debbie's 65 - year - old father </Li>

Cast of knocked up and this is 40