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