Posters for the film were hung at Place de l'Alma in Paris, near the entrance to the tunnel where the Princess of Wales died in a car accident in 1997. After an uproar, the posters were eventually removed at the request of French distributor Le Pacte.
When the camera first pans into Diana's hotel room at the very beginning of the movie, the wine glass seen on the dinner table is an exact replica of the glass used at the dinner where Dodi Fayed proposed to Diana at the Paris Imperial Hotel, minutes before their deaths. Dodi's father, Mohamed Al Fayed, had the wine glass preserved in an acrylic pyramid and it is now displayed as a memorial shrine at Harrod's in London, England.
Naomi Watts wore some of Diana's actual clothing and also donned a prosthetic nose, according to Vanity Fair.
Jessica Chastain was originally cast as Diana, Princess of Wales, but scheduling conflicts made her drop out.
Naomi Watts: [bare feet] Princess Diana is seen walking around barefoot on several occasions when in private throughout the film, a habit shared by both the real Diana and her actress Naomi Watts.