Peter Sellers

as Henry Orient

Tippy Walker

as Valarie Campbell Boyd

Merrie Spaeth

as Marian 'Gil' Gilbert

Paula Prentiss

as Stella Dunnworthy

Angela Lansbury

as Isabel Boyd

Tom Bosley

as Frank Boyd

Phyllis Thaxter

as Mrs. Avis Gilbert

Bibi Osterwald

as Erica 'Boothy' Booth