Naomi Watts will play Princess Diana in a new film that will centre around the final two years of her life and her love affair with a heart surgeon.
Caught In Flight will focus on Diana’s relationship with Hasnat Khan, the man she described as Mr Wonderful.
It will be directed by Oliver Hirschbiegel, whose 2004 film, Downfall, charted the last days of Adolf Hitler.
Watts, 43, replaces Jessica Chastain, who was attached to the project last year but pulled out.
“It is such an honour to be able to play this iconic role - Princess Diana was loved across the world and I look forward to rising to the challenge of playing her on screen,” the Telegraph quoted Watts as saying.
The film begins shooting later this year.
Hirschbiegel said he was “Delighted to have such a truly exceptional actor who embodies the warmth, humanity and empathy of such a global icon as Princess Diana”.
He described the plotline as “A love story between a princess locked in a tower and an ordinary man.”