Kayvan Novak
Brains / GDF Commander (voice) / Brains / Dr. Meddings (voice)

Rasmus Hardiker
Scott Tracy / Alan Tracy (voice)

Chris Jarman
The Mechanic / Hutch (voice)

David Menkin
Virgil Tracy / Gordon Tracy (voice)

David Graham
Parker / Vic (voice)

Sandra Dickinson
Grandma Tracy (voice)

Jenna Coleman
Baines (voice)

Adjoa Andoh
Colonel Casey (voice)

Thomas Brodie-Sangster
John Tracy (voice)

Angel Coulby
Kayo (voice)

Rosamund Pike
Lady Penelope (voice)

Teresa Gallagher
EOS (voice)

Tom Rosenthal
Brandon Berrenger (voice)

Jack Whitehall
Francois Lemaire (voice)

Reece Pockney
Paul Travers (voice)

Mark Gatiss
Dr. Quentin Questa (voice)

Asa Butterfield
Space Controller Conrad (Voice)

David Tennant
Tyco Reeves (Voice)

Emilia Clarke
Doyle (Voice)

Sylvester McCoy
Aezethril the Wizard (voice)