Rory Kinnear

Bedford

Mark Gatiss

Cavor

Alex Riddell

Jim

Reece Shearsmith

Moon

Lee Ingleby

Chessocks

Peter Forbes

Dad

Steve Pemberton

Sun

Philip Jackson

Voice of Grand Lunar

Julia Deakin

Mrs Fitt

Katherine Jakeways

Mum

Ian Hallard

Voice of Phi-Oo

Richard Rosson

Selenite (uncredited)

Damon Thomas