Raymond Massey as John Cabal / Oswald Cabal

Edward Chapman as Pippa Passworthy / Raymond Passworthy

Ralph Richardson as The Boss

Margaretta Scott as Roxana / Rowena

Cedric Hardwicke as Theotocopulos

Maurice Braddell as Dr. Harding

Sophie Stewart as Mrs. Cabal

Derrick De Marney as Richard Gordon

Ann Todd as Mary Gordon

Pearl Argyle as Catherine Cabal

Kenneth Villiers as Maurice Passworthy

Ivan Brandt as Morden Mitani

Anne McLaren as The Child

Patricia Hilliard as Janet Gordon

Charles Carson as Great Grandfather

Patrick Barr as World Transport Official (uncredited)

Noel Brophy as Irishman (uncredited)

John Clements as The Airman (uncredited)

Anthony Holles as Simon Burton (uncredited)

Allan Jeayes as Mr. Cabal (uncredited)

Pickles Livingston as Horrie Passworthy (uncredited)

George Sanders as Celestial Body (uncredited)

Abraham Sofaer as The Jew (uncredited)

Terry-Thomas as Man of the Future (uncredited)