Baby Mama is not entirely what you expect, and then at the same time it's everything you expect and a little bit more.

The very funny trailer that has been floating around for this movie for a while does a good job of selling the film. It's got quite a few excellent jokes, and the filmmakers show their potential audience a lot of the movie's main draw, the reteaming of SNL cohorts Tina Fey and Amy Poehler. Thankfully, it's not a case of the trailer showing you all the good parts, either--though I was surprised to discover that most of those big laughs are from the first ten or fifteen minutes of the movie.

Which is only the beginning of the many surprises that Baby Mama has waiting. For instance, did you know Steve Martin is in this movie? How about Greg Kinnear? Because neither of them have been in any of the promotions, despite both being a bonus in an excellent ensemble cast. Also, did you notice that none of the ads play up that the movie is written by Tina Fey, the scribe behind Mean Girls and the creator of 30 Rock? That's because she didn't write it, but the studio is probably hoping that most people think she did. It's actually written by the movie's director, Michael McCullers, a writer on SNL from 1997-1998 and a contributor to the second and third Austin Powers movies. He does a good job, I don't want to fault the guy, and I imagine Fey and Poehler have contributed a lot, but it does lack some of Tina Fey's wit.

The advertising for Baby Mama has been so ubiquitous, I doubt there are many reading this that don't already know what it's about. Tina Fey plays Kate, a successful businesswoman in her late thirties who has run out of options for having a baby herself. Deciding to go the surrogate route, she hires Angie (Poehler), a less upwardly mobile individual who is looking to make some cash in order to support her deadbeat common law husband (Dax Shepard). When things get bad at home, Angie leaves her husband and moves in with Kate, a control freak with specific ideas about how Angie should bake her baby. Hilarity ensues.

Except it maybe doesn't ensue at the constant pace some might be looking for. While you can pretty much guess that Kate will learn from Angie how to be less uptight and Angie will learn from Kate ways to improve herself, there are a few more wrinkles in their business relationship that aren't as easy to foresee. There is also a romantic subplot where Kate finally finds the man of her dreams in the form of Rob (Kinnear), a former lawyer who now runs a smoothie shop. Kate is moving the flagship store for the organic grocers she works for into Rob's neighborhood, fulfilling the dream of her hippy-dippy boss (Steve Martin, in a bang-on portrayal of a granola sell-out). Without giving too much away, the aforementioned wrinkles cause all of these relationships to get worse before they get better, and in true feel-good comedy fashion, everything has a way of working itself out.

Baby Mama has enough laughs to be worth the ticket price, and it never drags. The cast--which also includes Sigourney Weaver, Fred Armisen, Will Forte, and the always funny Romany Malco--are all expert comedians, with Maura Tierney thrown in for good measure as Kate's sister and the voice of experienced motherhood. The real stand-outs, though, true to form, are Poehler and Fey, who make a classic comic pairing. Fey is the brainy straight girl who plays off of Poehler's unlimited energy. The best jokes in the movie come out of their interaction, with Tina Fey's bad dancing maybe stealing the whole show.

Still, at times it feels like the duo are holding back, giving McCullers room to pluck a few heartstrings. Though you can see some of the turns coming from a mile off, the goopy bits do work, only really going all the way south in a ridiculous courtroom scene. (Honestly, having the judge grumble about how unorthodox things are doesn't keep the cliché from killing.) I just can't help wishing the movie was the one that they sell us in the trailer, that it moved a little faster, had way more jokes, and wasn't afraid to get kind of gross--like the Superbad of artificial insemination comedies. We admire these ladies for their silliness, not their sentimentality. This doesn't make Baby Mama a bad movie, not by any means, it just means that what could have been a comedy bullseye lands in that slightly less funny second circle around the bullseye instead.

Jamie S. Rich is a novelist and comic book writer. He is best known for his collaborations with Joelle Jones, including the hardboiled crime comic book You Have Killed Me, the challenging romance 12 Reasons Why I Love Her, and the 2007 prose novel Have You Seen the Horizon Lately?, for which Jones did the cover. All three were published by Oni Press. His most recent projects include the futuristic romance A Boy and a Girl with Natalie Nourigat; Archer Coe and the Thousand Natural Shocks, a loopy crime tale drawn by Dan Christensen; and the horror miniseries Madame Frankenstein, a collaboration with Megan Levens. Follow Rich's blog at Confessions123.com.