Eccentric aliens give a man the power to do anything he wants to determine if Earth is worth saving.
Simon Pegg
as Neil Clarke
Kate Beckinsale
as Catherine
Robin Williams
as Dennis the Dog (voice)
Rob Riggle
as Grant
Sanjeev Bhaskar
as Ray
Joanna Lumley
as Fenella
Marianne Oldham
as Rosie
Eddie Izzard
as Headmaster
Robert Bathurst
as James Cleverill
John Cleese
as Chief Alien (voice)
Judy Loe
as Canteen Lady
Brian Cox
as Self
