Mel Ferrer

as Maj. Gen. Robert Haines

as Jerry Parks

as French-Canadian Radio Speaker (voice) (uncredited)

as Fritz Gerlich

as Eric Brahm

as Prince Andrei Bolkonsky

as Harrison Page

as Cleander

as Harvey Wood

as Dr. Jekyll & Mr. Hyde (uncredited)

as General Murchison

as Father Neill

as Professor Carter

as Frenchy Fairmont

as Dr. Walker

as Mel Fields

as Massimo Oderisi

as Noel, Marquis de Maynes

as Arthur

as David Mendelssohn

as Self

as Benson Thacker

as Rudy DeMeyer

as Radcliffe (US version)

as Cornelius A. Woaegen, president of GTI

as Paul Berthalet

as Phillip Erickson

as Police superintendent

as Self - Actor / 1st Husband (archive footage)

Role: Producer

Role: Co-Director

as Joshua

as Le comte Henri de Chevincourt

as Father Serra (uncredited)

as Leopoldo De Karnstein

as Gobby

as Analog

as Professor Henry Douglas

as Philip Allan

as Robert Cohn

as Van Gould

as Hale Burton

as Patriarch

Role: Director

as Vera Husband

as Self

as Anthony Palandrini

as Dr. Ross

as Dr. Robert Cook

as King Eurich

as District Attorney Mannino

as Dr. Sidney Coleman

Role: Director

as Capt. Alfred Westerman

as Appolonius

Role: Director

as Dr. Scott Mason Carter

Role: Producer

as Nicholas Skinner

as Self (archive footage) (uncredited)

as Dr. Paolo Brogli

Role: Executive Producer

as Stephen Orlac

as CIA Chief Frankenheimer

as Judge Michael Lengel

as John Rickman

as Frederick

as Crown Prince Rudolph

as Dalton Harvey

as Roberto Micheli

as Sheriff

as Stephan Mathiesen

as Luís Bello

as Henrik

as Sheriff

as Self

as Doctor Harrison

as Self (archive footage)

as Juan Bautista de La Salle

as Giancarlo Barandero

as David

as El Greco (Domenico Teotocopulo)

as Peseti

as Arthur Orloff

as Carl Charnock

as George Matthews

as Aurelio Morelli

as Don Paolo Salinas

as Andrea Di Tula

as Self

Role: Director

as Marco

as Maj. Foster MacLain

as Dr. Sanford

as Gen. Franz von Clodius

Role: Producer

as Georges Gauthier

as Self (archive footage)

as Colonel Stone

as Anthony Durano

as Franz Bollenstein

as Self (archive footage)

as Andreas Heggener

as Armando Della Morra

Role: Director

Role: Director