The film was heavily marketed with links to Princess Diana (who is a direct descendant of Georgiana's family, The Spencers), using her image in the trailers, and with a tagline ("There were three people in her marriage") which is a play upon a quote attributed to the late Royal. Keira Knightley came out and denied the film had any links at all, stating that her character was interesting enough without any comparisons.
Costume designer Michael O'Connor based the blue "Fox uniform" ensemble worn by Keira Knightley in the whig political rally scene on portraits and political cartoons of Georgiana, Duchess of Devonshire, that were made in the late 18th century.
This is the second period film starring Keira Knightley that opens with the view of her walking across grass carrying something. In Pride & Prejudice (2005), she is walking across grass carrying a book. In this movie, she is carrying a hat with names for runners in a race.
The Tuscan red zone-front gown worn by Keira Knightley (known as the "Drunken Dress") had to be made in triplicate due to a stunt scripted for the scene. The costume required 36 meters of silk total for the three gowns, with green and gold lace applied by hand to each one.