Hành Tinh 51

John Cleese

Professor Kipple (voice)

Freddie Benedict

Eckle (voice)

Alan Marriott

Glar (voice)

Mathew Horne

Soldier #1 (voice)

James Corden

Soldier #2 (voice)

Alan Cumming

Alien Mailman (voice)

Frank Welker

Ripley / Rover (voice)

Jim Cummings

Lem's Dad (voice)

Renée Zellweger

Lem's Mom (voice)

Candi Milo

Teacher (voice)

Lewis Macleod

Additional Voices (voice)

Rupert Degas

Additional Voices / Chief Gorlock (voice) (uncredited)

Rebecca Front

Additional Voices (voice)

Vincent Marzello

Additional Voices (voice)

Emma Tate

Additional Voices (voice)