There's something that happens when supporting players make the leap to lead status - especially in comedy. Steve Carrell, Seth Rogen and Will Ferrell all started off stealing scenes from "bigger" names, and that's exactly how Jason Segel and Paul Rudd first found their way on celluloid. There must be something about the humility in performing comedy, then, because both of these guys are on sparkling form here, in this consistently hilarious and thoroughly enjoyable film.

Following up Forgetting Sarah Marshall by switching their roles slightly (Segel plays the eccentric pal, Rudd the square in need of a best man for his impending nuptials); a lot of the humour here comes from the often awkward situations when a guy tries to express his feelings to another man. Rudd's character, Peter, has no idea how to act around other guys as he's never really had male friends; this makes his attempts at forming friendships with other dudes watch-through-the-fingers cringe worthy. But director Hamburg (who also co-penned the mighty Zoolander) surrounds his leads with a barrage of immensely gifted comedy performers. Jon Favreau pops up sporadically, stealing scenes between directing blockbusters, while Jamie Pressley, JK Simmons and SNL star Andy Samberg all amuse thoroughly - even with fun size supporting roles. The plot can run out of steam slightly, and there's an inkling that Segel's character had a subplot that found the cutting room floor, but that matters little when you're generally too busy laughing to notice.

While the Rudd/Segel winning streak undoubtedly continues, Hamburg too must take some of the credit; after the disappointing Along Came Polly, he's finally directed a movie worthy of his top drawer writing ability. He knows exactly how to deal with these actors, who are pretty much the SAS of comedy improvisation - let them get on with it, and do the guts of your work in the editing room. He obviously has a strong gauge of what is funny, and that's plainly evident here. But this is still very much Rudd and Segel's movie, and somewhat predictably, they once again bring the funny.