Twilight actress Kristen Stewart will play Princess Diana in a new film about the late princess's break-up from Prince Charles, according to reports.

Stewart will star in Spencer, set in the early 1990s, which will be scripted by Peaky Blinders creator Steven Knight, Hollywood news sites say.

Director Pablo Larrain said Stewart was "one of the great actors around today".

The film will be set at Sandringham and will show Diana realising her marriage isn't working.

"We decided to get into a story about identity, and around how a woman decides somehow, not to be the queen," Larrain told Deadline.

"She's a woman who, in the journey of the movie, decides and realises that she wants to be the woman she was before she met Charles."

Lady Diana Spencer married Prince Charles in 1981. They separated in 1992 and divorced in 1996. She died in a car crash in Paris the following year.

Stewart is best known for playing Bella Swan in the hit Twilight franchise from 2008-12, and also appeared in last year's Charlie's Angels remake and 2014's Snow White and the Huntsman.

"Kristin can be many things, and she can be very mysterious and very fragile an ultimately very strong as well, which is what we need," added Larrain, who also made Jackie, 2016's biopic of Jackie Kennedy.

The Princess of Wales has been portrayed on screen before - Naomi Watts played her in the critically panned 2013 film Diana.

And the princess is due to appear in the fourth season of Netflix's royal drama The Crown, portrayed by newcomer Emma Corrin.