John Cleese Chief Alien (voice)
Kate Beckinsale Catherine
Simon Pegg Neil Clarke
Robin Williams Dennis the Dog (voice)
Michael Palin Kindly Alien (voice)
Eddie Izzard Headmaster
Joanna Lumley Fenella
Terry Gilliam Nasty Alien (voice)
Bill Jones Producer
Rob Riggle Grant
Emma Pierson Miss Pringle
Eric Idle Salubrious Gat (voice)
Gavin Scott Newsreader, Screenplay
David Annen Newsreader
Sanjeev Bhaskar Ray
Judy Loe Canteen Lady
Meera Syal Fiona
Robert Bathurst James Cleverill
Lucy Cork Stunt Double
Terry Jones Director, Scientist Alien (voice) / Van Driver, Writer
Jennifer Bell Hairstylist
Marianne Oldham Rosie
Brian Cox Self
Alexa Davies Sandwich Girl
Naomi Moore Set Decoration
Neville Phillips Author
Irene Lamb Casting
George Fenton Original Music Composer
Mike Medavoy Executive Producer
Ben Timlett Producer
James Kermack Policeman
John Kay Animation
Jud Charlton Mortician
Julian Rodd Editor
James Acheson Costume Design, Production Design
Peter Hannan Director of Photography
Ronan Summers Security Man
Oriol Navarro Animation
Lennon Clarke Bank Robber
Martyn Smith Animation
Mairi McHaffie Newsreader
Matt Fidler Animation
Du Wenlong Animation
Rob Hemmings Animation Director
Xu Yueyuan Animation
Dong Yixue Animation
Tan Weijian Animation
Yan Yan Animation
Xie Liyan Animation
Sun Xiaoxuan Animation
Beranger Maurice Animation
Li Jingxin Animation