Simon Pegg
Neil Clarke
Kate Beckinsale
Catherine
Rob Riggle
Grant
Sanjeev Bhaskar
Ray
Joanna Lumley
Fenella
Marianne Oldham
Rosie
Eddie Izzard
Headmaster
Robert Bathurst
James Cleverill
Judy Loe
Canteen Lady
Brian Cox
Self
Meera Syal
Fiona
Emma Pierson
Miss Pringle
David Annen
Newsreader
Mairi McHaffie
Newsreader
Gavin Scott
Newsreader
Robin Williams
Dennis the Dog (voice)
John Cleese
Chief Alien (voice)
Terry Gilliam
Nasty Alien (voice)
Eric Idle
Salubrious Gat (voice)
Terry Jones
Scientist Alien (voice) / Van Driver
Michael Palin
Kindly Alien (voice)
Alexa Davies
Sandwich Girl
Neville Phillips
Author
Ronan Summers
Security Man
Jud Charlton
Mortician
James Kermack
Policeman