This freaky, astutely riddlesome LA drama has been compared to David Lynch's Mulholland Drive. Its deliberately obtuse plot and meta-fictional bent also owes something to David Cronenberg's eXistenZ, Spike Jonze's Adaptation and that most sublime of nightmares, TV's The Larry Sanders Show. Whatever else, director-writer John August has great taste - if he steals, he steals from the best.

The story starts on a hot summer day, with a cute, successful TV actor Gary (Ryan Reynolds) accidentally burning his house down. After taking crack with a whore, he discovers his belly-button is missing. Does this mean he is God? Or that is he going ga-ga?

He gets placed under house arrest by his giggly, peculiar new PR (Melissa McCarthy), has a fling with a neighbour (Hope Davis), sees the number nine everywhere and gets freaked out by a deaf girl in a bus shelter.

Then it's all change, as we meet Gavin, a fêted, gay TV writer (Reynolds again), about to make a pilot for a drama series called Knowing, which features a deaf girl and an actress (McCarthy again) who's not at all to the liking of one of the network chiefs (Davis again). A reality TV show is following the pilot's progress. It's Gavin, however, who's in for a reality check.

A third segment sees the central actors switch roles again, as we enter Gavin's TV show and the multiple identities begin to make a kind of sense.

This may all sound rather too self-referential. Is there anything about California's neurotic community that hasn't been said? It seems the answer is yes and the person to thank is Melissa McCarthy. A superb actress with a - let's be blunt - chubby body, her jaggedly jolly presence poses all sorts of novel questions, mostly about sanity but also about sex. In the film's second section, her character is buddy and muse to a TV screenwriter - a role she has clearly played to her real-life best friend, August.

The other actors are uniformly excellent - Ryan Reynolds (last seen in Smokin' Aces) proves he's more than a cute Ben Affleck clone; look out, too, for Elle Fanning - the sister of Dakota.

August's direction, meanwhile, is cheekily assured. Back in 2000, age 30, this acclaimed writer got fired from DC, a show he'd helped create, and had a nervous breakdown. He obviously knows what it's like to go from hero to zero, from god to spod.

Let's avoid such extremes, and note merely that he's made a film that's funny ha-ha as well as funny peculiar; an exercise in navel-gazing that tickles all the senses.