Actress Naomi Watts is set to play Princess Diana in the upcoming biopic Caught In Flight. The Mullholland Dr. star is said to have taken over the role of the princess from The Tree of Life actress Jessica Chastain, who pulled out for unknown reasons.

Caught In Flight will be directed by Oliver Hirschbiegel, who directed the Oscar nominated 2004 film Downfall, about Hitler's last days. Caught In Flight will also follow a similar theme to Downfall; it is said to be about the last two years of Princess Diana's life, from her failed marriage to Prince Charles to her work as a humanitarian. According to Reuters, the initial plot is much different to the original idea, which was to focus on a secret affair between 'the people's princess' and heart surgeon Dr. Hasnat Kahn.

Caught In Flight is not the only biopic of Princess Diana in production; a film adaptation of the biography Closely Guarded Secret, written by the princess' bodyguard Ken Wharfe, will be adapted by Stephen Evans, with rumours that South African actress Charlize Theron will portray Diana. However, the Monster actress faces competition from British actresses, including Kiera Knightley and Carey Mulligan; Scarlett Johansson is also said to be interested in the part.

Caught In Flight is certainly not the only biopic about a British historical figure - Pride and Prejudice actor Colin Firth starred as King George VI in The King's Speech, while American actress Meryl Streep caused controversy in the UK when she was chosen to portray former Prime Minister Margaret Thatcher in The Iron Lady.