Peter Sellers as Robert Danvers

Goldie Hawn as Marion

Tony Britton as Andrew Hunter

Nicky Henson as Jimmy

Diana Dors as John's Wife

Judy Campbell as Lady Heather

Gabrielle Drake as Julia Halforde-Smythe

Nicola Pagett as Claire the Bride

Geraldine Sherman as Caroline

Thorley Walters as Manager of Carlton Hotel

Ruth Trouncer as Gilly Hunter

Françoise Pascal as Paola

Tom Marshall as Bryan

Raf De La Torre as Monsieur Le Guestier

Marianne Stone as Reporter

John Comer as John, the porter

Robin Parkinson as Le reporter aux lunettes

Constantine Gregory as Michel Le Guestier

Avril Angers as English Tourist in Lift

Georges Lambert as Floor Waiter

Margaret Lacey as Autograph Hunter at Wedding

Jack Armstrong as Wedding Guest (uncredited)

Eric Barker as Wedding Guest (uncredited)

Ernest Blyth as Wedding Guest (uncredited)

Christopher Cazenove as Nigel (uncredited)

Andre Charisse as Concierge (uncredited)

Mark Dignam as Wedding Guest (uncredited)

Hugh Elton as Photographer (uncredited)

Mabel Etherington as Wedding Guest (uncredited)

Muriel Greenslade as Wedding Guest (uncredited)

Pearl Hackney as Wedding Guest (uncredited)

Victor Harrington as Wedding Guest (uncredited)

George Holdcroft as Wedding Guest (uncredited)

Gordon Humphries as Reporter (uncredited)

Juba Kennerley as Wedding Guest (uncredited)

Roy Lansford as Waiter (uncredited)

Fred Machon as Sightseer at Wedding (uncredited)

Robin Parkinson as Reporter (uncredited)

James Payne as Reporter (uncredited)

Lance Percival as Willie the Bridegroom (uncredited)

Edith Raye as Wedding Guest (uncredited)

Bob Raymond as Hotel Porter (uncredited)

Terry Sartain as Reporter (uncredited)

Ian Selby as Wine Taster (uncredited)

John Serret as Elevator Operator (uncredited)

Caroline Seymour as Nigel's Girl Friend (uncredited)

Roy Skelton as Reporter (uncredited)

Alecia St Leger as Wedding Guest (uncredited)

John Tatham as Wedding Guest (uncredited)

John Timberlake as Cellarman (uncredited)

Cy Town as Photographer (uncredited)

Colin Vancao as Cigar-Smoking Wedding Guest (uncredited)

Mickey Varey as Constable (uncredited)