Dustin Hoffman as Wally Stanton

Vanessa Redgrave as Agatha Christie

Timothy Dalton as Archie Christie

Helen Morse as Evelyn

Celia Gregory as Nancy Neele

Paul Brooke as John Foster

Carolyn Pickles as Charlotte Fisher

Timothy West as Kenward

Tony Britton as William Collins

Alan Badel as Lord Brackenbury

Robert Longden as Pettelson

Yvonne Gilan as Mrs. Braithwaite

Sandra Voe as Therapist

Barry Hart as Supt. MacDonald

David Hargreaves as Sgt. Jarvis

Tim Seely as Capt. Rankin

Christopher Fairbank as Luland

Liz Smith as Flora

Peter Arne as Hotel Manager

Hubert Rees as Official at Literary Luncheon

Donald Nithsdale as Uncle Jones

Jill Summers as Nancy's Aunt

Geoff Tomlinson as Hotel Receptionist

John Joyce as Hotel Waiter

Irene Sutcliffe as Dress Shop Manageress

Ann Francis as Jane

Hope Johnstone as Royal Baths Clerk

John Ludlow as Royal Baths Clerk

Ray Gatenby as Official at Literary Luncheon

Tommy Hunter as Pierrot

Bert Ward as Pierrot

Harry Segal as Pierrot

Harry Segall as Hotel Trio

Jim Archer as Hotel Trio

Reginald Kilbey as Hotel Trio

Jonathan Benson as Head Waiter (uncredited)

Maxwell Craig as Policeman (uncredited)

Harry Fielder as Policeman (uncredited)

Tony Haygarth as Man Drinking Tea (uncredited)

Juba Kennerley as Gent Watching Billiards (uncredited)

Breandán O'Connor as Bellboy (uncredited)

Stan Richards as Hotel Porter (uncredited)

Pamela Austin as Pierrot