The film tells the true life story of Georgiana, Duchess of Devonshire, who was the great-great-great-great aunt of Diana, Princess of Wales.

In the film Knightley plays an aristocratic woman that is trapped in a marriage to a man who is in love with his mistress. It is this storyline that mimics the experiences of Princess Diana, who married Prince Charles only to discover that he was continuing a long-standing clandestine relationship with another woman.

Even the film’s tagline, "There were three people in her marriage", suggests a link to Diana’s story, as it bears a remarkable similarity to the words the princess used to describe her own situation in a highly candid 1995 television interview.

Speaking to the BBC, Keira Knightley was quick to play down the similarities in the stories, saying her character was "an interesting enough person to warrant a film completely about her without comparisons".

In fact the 23-year-old actress claims not to remember the story of Prince Charles and Princess Diana’s doomed marriage.

"I was 11 when Diana died, so I don’t really know what the actual story is so I don’t feel I can comment on the parallels," Knightley scolded reporters at a recent press conference.

Whether the Diana connection exists or not, The Duchess provides a fascinating insight into personal relationships in a society where divorce was taboo.

The film is also a visual feast as the architecture and fashions of 18th Century England are painstakingly recreated down to the smallest detail.