Baby Mama (12A)

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Tina Fey, who wrote a terrific comedy in Mean Girls, is also proving a pretty good comic actress, in 30 Rock.

What a pity this movie can't supply her with comparable material. She plays top exec Kate, who has just realised, aged 37, that she can't have a baby – so she pays a white-trash younger woman, Angie (Amy Poehler), to be a surrogate mother for her.

When Angie dumps her waster boyfriend and moves into Kate's flat, the scene is set for odd-couple sparks to fly – the slobette versus the control freak – but Michael McCullers' script is soft-headed to the point of inanity. Greg Kinnear will never play a wimpier love interest than the juice-bar owner he does here. Steve Martin fares better as Kate's New Age-blathering boss, whose boast about the "amazing salmon" he ate with Native Americans is almost worth the ticket price. Almost.

Watch Baby Mama trailer