The Duchess is a 2008 historical drama film directed by Saul Dibb, who co-wrote the screenplay with Jeffrey Hatcher and Anders Thomas Jensen, based on the 1998 book Georgiana, Duchess of Devonshire by Amanda Foreman, about the late 18th-century English aristocrat Georgiana Cavendish, Duchess of Devonshire. She was an ancestor of Diana, Princess of Wales, where the quote "There were three people in her marriage" in the promotional poster comes from.
The Duchess was released in 8 September 2008 in the United Kingdom. The film received generally positive reviews from critics. It won for Best Costume Design and was nominated for Best Art Direction at the 81st Academy Awards.
The young Georgiana is contracted in marriage to William Cavendish, Duke of Devonshire, with the expectation that she produce his male heir. Georgiana is quickly disillusioned by her husband, especially when Charlotte, an illegitimate child fathered by William whose mother has died, comes to live with them while Georgiana is pregnant. William expects Georgiana to tolerate the child's presence. He also suggests that she "practise mothering" on the young girl. When Georgiana gives birth to a girl, William is displeased. In his mind, he has fulfilled his obligations to her as her husband but, by failing to provide him with a legitimate male heir, she has failed in her obligations as his wife.
Georgiana becomes a leading light in fashionable society. She socialises with the young Lady Bess Foster at Bath and invites her to live with them since Bess has nowhere else to go. William has an affair with Bess, causing Georgiana to feel robbed of her only friend and betrayed by Bess. Bess tells Georgiana that her motive is to regain her three sons (whom her husband has taken from her), so she continues to live with them.
Georgiana starts an affair with Charles Grey. William is outraged when Georgiana suggests that since he has Bess, she should be allowed Charles. William rapes Georgiana; a male child is the product. Bess encourages the affair between Georgiana and Charles after the birth of Georgiana's son. Soon, the whole of London society learns of Georgiana's affair. William threatens to end Charles's political career and forbid Georgiana from seeing her children again if she does not end the relationship. After initially refusing, Georgiana ends her relationship with Grey but tells William that she is pregnant with Charles' child. She is sent to the countryside where she gives birth to her daughter with Grey, Eliza Courtney, who is given to the Grey family to raise as Charles' niece.
Georgiana finds comfort in Bess's friendship during her time of giving birth to Eliza. Georgiana and William come to terms with one another and, along with Bess, continue their lives together.
The after-credits reveal Georgiana secretly visits her daughter Eliza. Eliza goes on to name her own daughter Georgiana, after her mother. Charles later becomes Prime Minister under William IV. Before she dies, Georgiana permits William and Bess to marry.
The Duchess was produced by British Qwerty Films and American Magnolia Mae Films, with financial support from BBC Films, French Pathé and Italian BIM Distribuzione. The film was shot at Twickenham Film Studios and on location at Chatsworth, Bath, Holkham Hall, Clandon Park, Kedleston Hall, Somerset House, King's College London and the Old Royal Naval College in Greenwich.
Regarding lead actress Keira Knightley, director Saul Dibb said The Duchess was "a chance to take a character from late childhood – she's married at 17 – into full adulthood, 10 years later." It was also a chance for Knightley to work with Ralph Fiennes, whom she regarded as one of her most accomplished co-stars to date; Dibb said, "When I said, 'We've got Ralph interested in playing the Duke,' we both took a gulp and went, 'F---.' [sic] ... But I didn't for one second feel that she wasn't up to the task." Originally, the film was to be directed by Susanne Bier.