Game Of Thrones Prequel House Of Dragons Adds Four More Cast Members In Major Roles

HBO's upcoming Game of Thrones spin-off, House of the Dragon, has cast four additional actors who will appear in the prequel series in major roles.

The newly announced actors include Prince of Persia: The Sands of Times's Steve Toussaint, who will play Lord Corlys Velaryon AKA The Sea Snake, a "famed nautical adventurer." Eve Best from The King's Speech will play Princess Rhaenys Velaryon, who is a dragonrider and the wife of Corlys Velaryon.

Harry Potter actor Rhys Ifans has been cast as Otto Hightower, the hand of the king. Crazy Rich Asians star Sonoya Mizuno will play Mysaria, a woman who came from nothing and rose to immense power.

House of the Dragon takes place 300 years before the events of Game of Thrones and is based on George R.R. Martin's Fire & Blood series. It focuses on House Targaryen, the family of Daenerys Targaryen from the main Game of Thrones show.

These new cast members join a lineup that already includes Doctor Who actor Matt Smith as Daemon Targayen, Paddy Considine as King Viserys Targaryen, Olivia Cooke as Alicent Hightower, and Emma D'Arcy as Princess Rhaenyrd Targaryen.

You can see the full descriptions of the newly announced characters below. House of Dragons does not have a release date yet.

Game of Thrones House of the Dragons New Cast Members:

Steve Toussaint as Lord Corlys Velaryon aka "The Sea Snake." The lord of House Velaryon, a Valyrian bloodline as old as House Targaryen, "The Sea Snake," is the most famed nautical adventurer in the history of Westeros. He built his house into a powerful seat that is even richer than the Lannisters and that claims the largest navy in the world.

Eve Best as Princess Rhaenys Velaryon. A dragonrider and wife to Lord Corlys Velaryon, "The Queen Who Never Was" was passed over as heir to the throne at the Great Council because the realm favored her cousin, Viserys, simply for being male.

Rhys Ifans as Otto Hightower, the Hand of the King, who loyally and faithfully serves both his king and his realm. As the Hand sees it, the greatest threat to the realm is the king's brother, Daemon, and his position as heir to the throne.

Sonoya Mizuno as Mysaria. She came to Westeros with nothing, sold more times than she can recall, and could have wilted...but instead she rose to become the most trusted--and most unlikely--ally of Prince Daemon Targaryen, the heir to the throne.