The Shaun of the Dead boys have come a long way. Having followed up Shaun’s critical success with UK box office smash Hot Fuzz, stars Simon Pegg and Nick Frost and director/co-writer Edgar Wright were firmly established as major British talent. Last summer Wright took his first shot at a big American movie with comic-book adaptation Scott Pilgrim Versus the World, a disappointment at the box office but an impressive demonstration of his developing creative muscle. Now, after a few high-profile solo acting gigs (most notably Pegg’s turn as Scotty in 2009’s Star Trek), Pegg and Frost re-team as writers and co-stars in Paul, a tale of two English sci-fi nerds who encounter a real-life alien called Paul while on a road-trip through America’s UFO hotspots. But while the film certainly won’t disappoint fans of the duo’s brand of comedy, Pegg and Frost could have done with following Wright’s more adventurous lead; as it is they stick too closely to their comfort zones both as writers and actors, and despite its theme, the film is more run-of-the-mill than out of this world.

In fact, to begin with, Paul could almost be a Transatlantic episode of Spaced, with the geek-pal relationship between Pegg and Frost’s Graeme and Clive riffing on exactly the same notes that made Tim and Mike so endearing in that television show. It’s still a routine that works though, and there are plenty of laughs to be had in the script’s many recurring jokes – one involving characters reeling off the increasingly ridiculous titles of a cult sci-fi author’s books is particularly funny. Director Greg Superbad Mottola develops a suitably atmospheric tone, which entireley fits the script’s spirit of both revering and mocking sci-fi conventions (in both senses), while Jason Bateman provides strong support as a menacing FBI agent on the hunt for Paul.

And what of the title character? Happily, Paul is the film’s greatest asset. A fantastically realised CG creation who gets all the funniest lines and is brilliantly voiced by Seth Rogen, he’s the spark of originality that makes this film worthwhile.

General release, Mon 14 Feb.