Freddie Highmore as Arthur Montgomery

Mia Farrow as Granny

Robert Stanton as Armand

Penny Balfour as Rose Montgomery

David Gasman as The Mechanic

Antony Hickling as Douglas

Dashiell Eaves as Simon

Joseph Rezwin as Brad

Cooper Daniels as George Lucas

Ron Crawford as Archibald

Stuart Rudin as Francis

Steve Routman as Dr. Stitch

Peter Hudson as General Montgomery

Lou Reed as Maltazard (voice)

Selena Gomez as Selenia (voice)

Iggy Pop as Darkos (voice)

Mike Powers as Grafitti Artist (voice)

James A. Baffico as Martin Baltimore (voice)

Jean Bejote Njamba as Bogo Chief

Laurent Mendy as Bogo

Norman Stokle as Mayor