Ralph Fiennes, Hayley Atwell and Dominic Cooper have joined Keira Knightley in the cast of Saul Dibb's "
The Duchess," which starts shooting Sept. 23 in London.
Based on Amanda Foreman's biography of the scandalous 18th century English aristo Georgiana, Duchess of Devonshire, the movie is being co-financed by Pathe and BBC Films.