Kitty (1945)

In 1783 London, Kitty, a saucy wench of the slums, meets painter Gainsborough by stealing his shoes. He paints her as an "anonymous lady" who excites the interest of his noble friends, notably penniless Sir Hugh Marcy, who schemes to pass Kitty off as a genuine lady (a formidable task) and marry her off for financial gain. But Kitty has her own ideas about the uses of matrimony. Lots of decolletage.