Peter Sellers

Grand Duchess Gloriana XII / Prime Minister Count Rupert Mountjoy / Tully Bascombe

Jean Seberg

Helen Kokintz

William Hartnell

Will Buckley

David Kossoff

Professor Alfred Kokintz

Leo McKern

Benter

MacDonald Parke

General Snippet

Austin Willis

United States Secretary of Defense

Timothy Bateson

Roger

Monte Landis

Cobbley

Alan Gifford

Air Raid Warden

Colin Gordon

BBC Announcer

Harold Kasket

Pedro

Guy Deghy

Soviet Ambassador (uncredited)

Eve Eden

Spectator (uncredited)

Bill Edwards

Army Captain (uncredited)

Lionel Murton

American General at the Pentagon (uncredited)

Bill Nagy

U.S. Policeman (uncredited)

Robert O'Neil

Reporter (uncredited)

Mavis Villiers

Telephone Operator (uncredited)