A few years ago Judd Apatow redefined the "R-Rated" comedy (a 16 cert here) by using talented comedic actors and allowing them to improvise heavily. The resulting films he directed and produced created new stars and a new way of making funny on film. Here, Ben Stiller and Vince Vaughn struggle to inject life into a silly, overstuffed sci-fi comedy in a similar way that Paul Rudd did with Wanderlust. Just putting funny people in your movie will not make it funny and The Watch is another prime example of that.

Stiller is a pedantic sort who lives a reserved existence in a quiet Middle American suburb. He busies himself with retail management job, attempting to make a baby with his understanding wife and creating numerous community clubs. When one of his employees is brutally murdered he starts a neighbourhood watch programme, which attracts Vince Vaughn's boisterous construction worker, Jonah Hill's possible sociopath and Richard Ayoade's awkward Brit. Just as the lads are beginning to enjoy the volunteer gig, they realise they're in the midst of an alien invasion.

Balancing tone in a genre hybrid is always difficult and despite the big name cast and high concept The Watch struggles to do either the comedy or the sci-fi justice. There is no real good role here for anyone, and director Schaffer isn't really sure what kind of movie he's making so just lets the a-listers run riot. Stiller at least gets that he's the straight man, while Vaughn tries to go back to scene-stealing supporting actor territory after a couple of poor starring roles; ostensibly a wise move from Vaughn, he's played this guy better in Wedding Crashers and Old School. Hill seems to be challenging Seth Rogen's underrated work in Observe and Report while Ayoade's deadpan delivery is sporadically funny but feels like it's from a different movie.

Coming from a comedic director with some pedigree (Schaffer is one third of comedy group The Lonely Island), it's a possibility that some very good gags ended up on the cutting room floor. Or it's possible that the material wasn't there to begin with and one big name in the cast attracted the other talent and collectively they attempted to shine a turd. Either way it doesn't work and is rarely funny.