The “Game of Thrones” prequel series “House of the Dragon” at HBO has cast Milly Alcock and Emily Carey in recurring roles.

“House of the Dragon” is set a few hundred years prior to the events of “Game of Thrones” and tells the story of House Targaryen and the Targaryen civil war that became known as the “Dance of the Dragons.”

Alcock has been cast as the young version of Princess Rhaenyra Targaryen, the king’s first-born child, she is of pure Valyrian blood, and she is a dragonrider. Many would say that Rhaenyra was born with everything, but she was not born a man. The elder version of Rhaenyra will be played by Emma D’Arcy as previously announced.

Carey will appear as the young version of Alicent Hightower, the daughter of Otto Hightower, the Hand of the King, and the most comely woman in the Seven Kingdoms. She was raised in the Red Keep, close to the king and his innermost circle; she possesses both a courtly grace and a keen political acumen. As previously announced, Olivia Cooke will play the elder version of Alicent Hightower.

They join a cast that already includes D’Arcy, Cooke, Paddy Considine, Matt Smith, Steve Toussaint, Rhys Ifans, Eve Best, Sonoya Mizuno, and Fabien Frankel.

Alcock is repped by Management 360 in the U.S. and Shanahan Management in Australia. Carey is repped by Curtis Brown Group in the UK, as well as Grandview and UTA in the U.S.

HBO has given “House of the Dragon” a 10-episode order with an eye toward a 2022 debut. The start of production was announced on April 26. It is based on George R.R. Martin’s book “Fire & Blood.” Martin recently signed a five-year overall deal to create content for HBO and HBO Max.

Miguel Sapochnik and Ryan Condal will serve as co-showrunners and will also serve as executive producers along with Martin and Vince Gerardis. Martin and Condal co-created the series. Sara Lee Hess will also serve as writer and executive producer; Ron Schmidt will also executive produce. Sapochnik will direct the pilot and additional episodes. Clare Kilner and Geeta V. Patel will also direct with Greg Yaitanes directing and co-executive producing.

(Pictured: Milly Alcock, left; Emily Carey, right)