Inside almost every Sigourney Weaver flick is a subtle theme of maternal instinct.

Gorillas In The Mist, Heartbreakers, Aliens, I guess the exception to the rule would be her bouncing, baby xenomorph she lovingly blew through a hole in Alien: Resurrection - that sort of behaviour will simply result in an empty-handed postman come Mother’s Day.

While her latest project has its maternal thread slapped right over its booty like a Banksy graffiti’d nappy, this time Weaver's not playing mummy, she’s the corporate head of an agency that makes mummies.

She'll be teaming up with actress Tina Fey, who recently broke from her US show, 30 Rock, and Mean Girl’s  Amy Poehler in the comedy, written and directed by Undercover Brother scriber, Michael McCullers.

Fey will play a career driven, wannabe mum, who after discovering that she’s infertile, puts everything on the line to make parenthood happen. Phoeler will play an oddball surrogate mother and Weaver the person responsible for bringing the characters together.

Baby Mama is expected to begin filming next week. There’s no release date set for the movie, but at a guess we’d say it could pop out in about nine months.