We're all guilty of doing it sometimes: seeing Jennifer Aniston's Hollywood smile beaming down at us from a promo poster and instantly thinking; "That's going to be rubbish anyway." Her last two films, 'The Bounty Hunter' and 'Love Happens', have done nothing to convince us otherwise, both failing to push Aniston out of that 'Rachel from Friends' niche she seems to have nestled into.

That's why it comes as such a delightful and unexpected shock that 'The Switch', along with hilarious 'Arrested Development' star Jason Bateman, manage to recapture Aniston's best 'Marley and Me' days, to deliver a topical and heart-warming film - one to warrant such a smug smile on those posters.

Desperate to have a baby, 40-something-year-old Kassie (Aniston) goes in search of the perfect donor to give her what she wants, instantly disregarding her perpetual best friend Wally (Bateman). A little perturbed about the obvious burn, a very drunk Wally manages to switch the sperm of the donor with his own, at Kassie's getting pregnant party, with no recollection of the event the next morning.

Seven years later, and with a mini Wally in tow, an unaware Kassie moves back to New York. Will she notice the similarities between her quirky best friend and her equally kooky son - and how will Wally break it to her?

The underrated star of this film is Bateman as the wonderfully neurotic and loveable Wally. He manages to combine his comedic talents with his infectious personality, to transform 'The Switch' from a clichéd rom-com into a charming screen pleasure. A little unjustly, it seems like he was forgotten in the run-up to this film, something that can understandably happen in the shadow of Jennifer Aniston's celebrity status. Aniston doesn't overdo it, and instead opts for a back seat to Bateman's abilities.

If Abigail Breslin melted your heart in 'Little Miss Sunshine', then you'll love the socially awkward Sebastian (Robinson) whose excessive preoccupation with his health leaves him a bundle of nerves. A little sad, but he's cute all the same.

The film does, however, have its unappealing aspects. The topic of artificial insemination could have been delved into further and approached in a different way, to make the storyline more believable and add edginess. Also, while Bateman plays a stormer as Wally, his character is fairly clichéd; once he realises his paternal instincts he turns from a complete pessimist to a mascot for optimism.

Although it failed at the box office in the US, this uplifting film doesn't pretend to be anything it's not. It's about taking opportunities when they present themselves and having no regrets. If it's a dash of humour and an appealing plot you're after then 'The Switch' is certainly a nice way to spend a rainy afternoon. If not, then maybe stick to looking at the posters.

Sarah Carty