HBO confirms full cast and director for Game of Thrones prequel

HBO has revealed the director and seven more cast members of the upcoming Game of Thrones prequel pilot.

According to Deadline, British filmmaker S.J. Clarkson (Marvel's Jessica Jones, The Defenders) will direct and executive produce the prequel, which has been written by Jane Goldman (X-Men: First Class) and George R. R. Martin.

The prequel has also added seven rising stars to its cast, including Naomi Ackie (Star Wars: Episode IX), Jamie Campbell Bower (The Twilight Saga, Harry Potter) and Georgie Henley (the Narnia Franchise).

Denise Gough, Sheila Atim, Ivanno Jeremiah, Alex Sharp and Toby Regbo round out the ensemble, joining the previously cast Naomi Watts and Josh Whitehouse.

From left: Naomi Watts, Naomi Ackie, Georgie Henley and Jamie Campbell Bower will star in the untitled Game of Thrones prequel. Photos / Getty Images

The untitled prequel is said to take place thousands of years before the events of Game of Thrones, and is thought to chronicle the origins of the White Walkers and Westeros' descent from the golden Age of Heroes.

Little is known about the characters, though Watts has been confirmed to be playing "a charismatic socialite hiding a dark secret".

Clarkson was previously attached to make a fourth Star Trek film, which Deadline reports has now been shelved. She most recently directed and executive produced Netflix's Collateral, starring Carey Mulligan.

The eighth and final season of Game of Thrones is expected to premiere in April this year.

Following the Golden Globe Awards on Monday, Variety reported HBO boss Richard Plepler as saying the final season will be like watching "six movies".