First official images from 'Game of Thrones' prequel 'House of the Dragon' released - CNN

D'Arcy has previously appeared in TV series "Truth Seekers" and "Hanna."

Matt Smith, best known for appearing in "The Crown" and "Doctor Who," will play heir to the throne Prince Daemon Targaryen, the King's younger brother who is known as a fierce warrior.

Lord Corlys Velaryon, known as "The Sea Snake," will be played by Steve Toussaint, who has previously appeared in "Prince of Persia" and "Judge Dredd." House Velaryon is a Valyrian bloodline as old as House Targaryen.

Olivia Cooke will play Alicent Hightower, "the most comely woman in the Seven Kingdoms," according to HBO.

Cooke previously appeared in "Sound of Metal" and "Vanity Fair."

Her character is the daughter of Otto Hightower, who will be played by Rhys Ifans -- best known for roles in "The Amazing Spider-Man" and "Notting Hill."

CNN and HBO share the same parent company, WarnerMedia.

Writer Martin is also working on a "Game of Thrones" stage show to build on the success of the TV series.

In March, Martin told the Hollywood Reporter he is developing a live stage show for Broadway, the West End and Australia to hopefully debut in 2023.