Sigourney Weaver is set to star alongside Tina Fey and Amy Poehler in the comedy BABY MAMA, which is expected to begin filming next month. In the film, Fey will play a woman looking to get pregnant but finds she is unable. She turns to a surrogate (Poehler) who is, well, pretty much insane. Weaver will play the head of the company who offers the surrogate. She may also be insane but I’m not sure about that. As much as I love Weaver and her body of work, her current job narrating the “Planet Earth” documentaries has me yanking my hair out. It’s not so much her voice as that awful copy they have her reading. Luckily she’s got James Cameron’s AVATAR on the way as well so things are looking up for Ms. Weaver. MAMA was written and will be directed by “SNL” vet Michael McCullers who also wrote the latter two AUSTIN POWERS movies and UNDERCOVER BROTHER. Fey is currently on hiatus from her NBC series “30 Rock,” which was just picked up for a 2nd season.