"Couture is for grannies," declared Brigitte Bardot in 1964, as high fashion came under increasing threat from the ready-to-wear industry. But just three years later, another cool, blonde French movie star, Catherine Deneuve, helped reconnect couture with a new generation. William Banks-Blaney explores how Yves Saint Laurent's costumes for the 1967 film chart the evolution of Deneuve's character from bourgeois housewife to masochistic prostitute. And he explains how, in a decade of enormous upheaval, Belle de Jour had a far darker message hidden within its haute couture.