Peter Sellers character Grand Duchess Gloriana XII / Prime Minister Count Rupert Mountjoy / Tully Bascombe
Jean Seberg character Helen Kokintz
William Hartnell character Will Buckley
David Kossoff character Professor Alfred Kokintz
Leo McKern character Benter
MacDonald Parke character General Snippet
Austin Willis character United States Secretary of Defense
Timothy Bateson character Roger
Monte Landis character Cobbley
Alan Gifford character Air Raid Warden
Colin Gordon character BBC Announcer
Harold Kasket character Pedro
Guy Deghy character Soviet Ambassador (uncredited)
Eve Eden character Spectator (uncredited)
Bill Edwards character Army Captain (uncredited)
Mabel Etherington character Ada - Lady in Waiting (uncredited)
Muriel Greenslade character Lady in Waiting (uncredited)
Fred Haggerty character Fenwickian (uncredited)
Juba Kennerley character Maybury (uncredited)
George Margo character O'Hara (uncredited)
Lionel Murton character American General at the Pentagon (uncredited)
Bill Nagy character U.S. Policeman (uncredited)
Robert O'Neill character Reporter (uncredited)
Pat Ryan character American General (uncredited)
Stuart Saunders character Sergeant (uncredited)
Fred Stroud character Fenwickian (uncredited)
John Tatum character American Admiral (uncredited)
Mavis Villiers character Telephone Operator (uncredited)
Fred Wood character Bird Seller (uncredited)
