Rex Harrison
Cecil Fox
Susan Hayward
Mrs. Sheridan
Cliff Robertson
William McFly
Capucine
Princess Dominique
Edie Adams
Merle McGill
Maggie Smith
Sarah Watkins
Adolfo Celi
Inspector Rizzi
Hugh Manning
Volpone
David Dodimead
Mosca
Mimmo Poli
Cook (uncredited)
Luigi Scavran
Massimo (uncredited)
Jack Benny
Violinist Outside Restaurant (uncredited)
Herschel Bernardi
Oscar Ludwig (uncredited) (scenes deleted)
Massimo Serato
The Pretender (uncredited) (scenes deleted)