Jack Farthing has been signed to portray Prince Charles in filmmaker Pablo Larrain's Spencer, which has Kristen Stewart playing Princess Diana.

The film, which will address the Princess of Wales' decision to leave Prince Charles while holidaying with the British royals, has a script from Steven Knight of Peaky Blinders fame.

The story takes place over three days, in one of Princess Diana's final Christmas holidays in the House of Windsor in their Sandringham estate in Norfolk, England, as per the film's synopsis.

Farthing, best known for the drama series Poldark, joins the cast along with actors Timothy Spall, Sally Hawkins, and Sean Harris.

Larrain, who has directed films like Jackie and Neruda, will also produce this project, along with Juan de Dios, Jonas Dornbach, Janine Jackowski, and Paul Webster.

The makers plan to release the film in the autumn of 2022, to coincide with the 25th death anniversary of Princess Diana.

Most recently, actors Emma Corrin and Josh O'Connor played the former royal couple in the hit Netflix drama, The Crown. The two actors picked up Golden Globes and Critics Choice Awards for their performances.