HBO Max has released first details and images for upcoming Game of Thrones spinoff House of the Dragon:

Based on George R.R. Martin’s “Fire & Blood,” the series, which is set 300 years before the events of “Game of Thrones,” tells the story of House Targaryen.  HOUSE OF THE DRAGON recently began production and will debut on HBO and be available to stream on HBO Max in 2022.
 
Featured cast include the following:
 
Emma D’Arcy as “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.
 
Matt Smith as “Prince Daemon Targaryen”: The younger brother to King Viserys and heir to the throne.  A peerless warrior and a dragonrider, Daemon possesses the true blood of the dragon.  But it is said that whenever a Targaryen is born, the gods toss a coin in the air…
 
Steve Toussaint as “Lord Corlys Velaryon” (“The Sea Snake”): Lord of House Velaryon, a Valyrian bloodline as old as House Targaryen.  As “The Sea Snake,” the most famed nautical adventurer in the history of Westeros, Lord Corlys built his house into a powerful seat that is even richer than the Lannisters and that claims the largest navy in the world.
 
Olivia Cooke as “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.
 
Rhys Ifans as “Otto Hightower”: The Hand of the King, Ser Otto 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.
 
Credits:
Co-Creator/Executive Producer: George R.R. Martin
Co-Creator/Co-Showrunner/Executive Producer/Writer: Ryan Condal
Co-Showrunner/Director of Pilot and Additional Episodes/Executive Producer: Miguel Sapochnik
Executive Producer: Vince Gerardis
Executive Producer/Writer: Sara Hess
Executive Producer: Ron Schmidt
Director: Clare Kilner
Director: Geeta V. Patel
Director/Co-Executive Producer: Greg Yaitanes 
Co-Executive Producer: David Hancock
Consulting Producer: Jocelyn Diaz
Based on George R.R. Martin’s “Fire & Blood.”