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

John Fiedler as Sidney

Fred Stewart as Doctor

Al Lewis as Store Owner

Peter Duchin as Joe Daniels

Philippa Bevans as Emma Hambler

Jerry Jarrett as (as Jerry Jerrett)

Jane Buchanan as Lillian Kafritz

Peter Turgeon as Orchestra Member

William Hinnant as

Colin Romoff as

William LeMassena as (as William Le Massena)

Claudia Morgan as Drunk Woman at Christmas Party