Stewart Granger
— Beau Brummell
Elizabeth Taylor
— Lady Patricia
Peter Ustinov
— George, Prince of Wales
Robert Morley
— King George III
James Donald
— Lord Edwin Mercer
James Hayter
— Mortimer
Rosemary Harris
— Mrs. Fitzherbert
Paul Rogers
— William Pitt
Noel Willman
— Lord Byron
Peter Dyneley
— Midger
Charles Carson
— Sir Geoffrey Baker
Ernest Clark
— Dr. Warren
Peter Bull
— Mr. Fox
Mark Dignam
— Mr. Burke
Desmond Roberts
— Colonel
David Horne
— Thurlow
Ralph Truman
— Sir Ralph Sidley
George De Warfaz
— Dr. Dubois
Henry Oscar
— Dr. Willis
Harold Kasket
— Mayor
Howard Lang
— Hecker (uncredited)