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