Neil Clarke

Simon Pegg

Ray

Sanjeev Bhaskar

James Cleverill

Robert Bathurst

Catherine

Kate Beckinsale

The Headmaster

Eddie Izzard

Fenella

Joanna Lumley

Grant

Rob Riggle

Rosie

Marianne Oldham

Miss Pringle

Emma Pierson

Fiona

Meera Syal

Steve

James David Robinson

Canteen Lady

Judy Loe

Dennis

Robin Williams

Lavender

Ellie Green

Extraterrestrial

John Cleese

Extraterrestrial

Eric Idle

Self

Professor Brian Cox

Professor Brian

Brian Cox

Policeman

James Kermack

Extraterrestrial

Terry Jones

Reporter

Brenda Emmanus

Kindly Alien (voice)

Michael Palin

Author

Neville Phillips

Nasty Alien (voice)

Terry Gilliam

Newsreader

David Annen

Newsreader

Mairi McHaffie

Mr. Eriksson

Edward Fisher

Newsreader

Gavin Scott

Police Inspector

Simon Coleman

Security Man

Ronan Summers

Sandwich Girl

Alexa Davies

Newsreader

Richard Suchet

Mortician

Jud Charlton

Ray Worshiper

John Bedford

Ray Worshiper

Marli Bland

Ray Worshiper

Bassia Forrest

Ray Worshiper

Liliana Gane

Ray Worshiper

Lorna Lacey

Ray Worshiper

Debbie Nash

Ray Worshiper

Christian Palmer

Ray Worshiper

Zara Sorensen

Ray Worshiper

Christopher Weeks

Documentary Voice (voice)

Christopher Chesser

Pink Policeman

Robert Jones

Alien Computer Voice (voice) / Señorita Lopez

Margarita Doyle

Pink Policeman

Chris Daniels

Pink Policeman

Charlie Richards

Baby

Samuel Timlett

Bank Robber

Lennon Clarke

Party Guest (uncredited)

Lasco Atkins

Photographer (uncredited)

Hannah Blamires

Passerby (uncredited)

Stuart Budd

Zombie (uncredited)

Marat Khairoullin

Celebrity (uncredited)

Jorge Leon

Book Launch Guest (uncredited)

Tremayne Miller

Ray Worshiper (uncredited)

Lockhart Ogilvie

Father (uncredited)

Tony Pankhurst

Man at Party (uncredited)

Alan Yentob