Tom Baker

The Doctor / Meglos

Lalla Ward

Romana II

John Leeson

K9 (voice)

Bill Fraser

General Grugger

Frederick Treves

Lieutenant Brotadac

Edward Underdown

Zastor

Jacqueline Hill

Lexa

Colette Gleeson

Caris

Crawford Logan

Deedrix / Meglos (voice) (uncredited)

Christopher Owen

Earthling