Jamie Dornan has joined the new Marie Colvin biopic 'A Private War'.

Jamie Dornan

Jamie Dornan

The 35-year-old actor - who is best known for portraying Christian Grey in the 'Fifty Shades' movies - has joined Rosamund Pike in the new film, which is set to be helmed by 'Cartel Land' director Matthew Heineman, Variety reported.

'A Private War' will follow the American journalist Marie Colvin, who worked for the British newspaper The Sunday Times from 1985.

She covered major conflicts across the world - from Chechyna to Sri Lanka where she lost the sight in her left eye in 2001.

Colvin was killed during a rocket attack while covering the Seige of Homs in Syria in 2012 while reporting for her newspaper.

Pike, 38, will star as the journalist but Dornan's role in the movie is yet to be revealed.

The script, penned by Arash Amel, is based on a 2012 Vanity Fair article, written by Marie Brenner, entitled 'Marie Colvin's Private War'.

Meanwhile, producing is Thunder Road Pictures' Basil Iwanyk and Kamala Films' Marissa McMahon, with Erica Lee serving as the executive producer.

Production is planned for an October start in the UK and Middle East.

Pike has just finished filming Scott Cooper's 'Hostiles' opposite Christian Bale and Ben Foster.

Dornan, on the other hand, is set to reprise his role as Christian Grey in the final instalment of the popular franchise, which is set to be released next Valentine's Day.

The Hollywood hunk is also set to appear as Will Scarlet in 'Robin Hood Origins'.

The film - which also features Taron Egerton as the titular character, Jamie Foxx as Little John, Eve Hewson as Maid Marian, Ben Mendelsohn as the Sheriff of Nottingham and Tim Minchin as Friar Tuck - is scheduled to be released on September 21, 2018.