Simon Pegg doesn't think an actor's portrayal of an alien can match up to a computer-generated creature.

The actor stars with long-time collaborator Nick Frost in new comedy 'Paul' - which follows to pals who pick up a hitchhiking extra-terrestrial during a road trip across the US - and he is pleased they opted to use Seth Rogen's voice talents with a digital being, rather than cast someone in the title role.

He said: "I think we lucked out with Paul. I look back at the cast, and I don't think there's a single human being that might have been better."

As well as 'Paul', Simon and Nick can next be seen together in 'The Adventures of Tintin: Secret of the Unicorn' - the Steven Spielberg-directed movie in which they play detectives Thompson and Thompson - and were amazed at the attention the film brought them at the world-famous Comic-Con event in San Diego, California.

Simon, 39, explained to FHM magazine: "We were like prisoners in our hotel room. It's a small dose of that level of fame that I Hope never to achieve. People like Tom Cruise and Brad Pitt, that's what their life is like. It's like being in The Beatles or something."

Nick jokingly added: "It's like being a Beatle, at a Beatle convention."