TINA FEY and AMY POEHLER are at it again! The former "Saturday Night Live" Weekend Update pals have teamed up for the big-screen comedy 'Baby Mama,' in theaters Friday, and we're at their big premiere at the Tribeca Film Festival!

"It was great to work with a friend you know so well [and it shows onscreen]," Amy tells ET. As for who she'd choose to be her surrogate mother, she jokingly replied, "I would choose [my co-star] DAX SHEPARD to be the mother of my child. I have a lot of faith in him."

Tina remarked that it was a pleasure to film the movie in New York, doubling as Philadelphia, which is exactly what the Tribeca Film Festival represents. And the premiere also created a red-carpet reunion opportunity for classic "SNL" funnymen CHEVY CHASE and STEVE MARTIN, who has a cameo in the film.

In the movie, Tina plays Kate, a successful, single businesswoman who can't get pregnant, despite her best efforts. She hires the blue-collar Angie Ostrowiski (Amy) to be a surrogate mother, but her life is turned upside down when Angie shows up at her doorstep with no place to live. A comic battle of wills ensues as they struggle to find common ground – and learn that there are two kinds of family: the one you're born to and the one you make.

Also starring SIGOURNEY WEAVER and HOLLAND TAYLOR, the film marks the directorial debut of "SNL" and 'Austin Powers' screenwriter MICHAEL McCULLERS.