The legends of House Targaryen have assembled.

The Game of Thrones prequel series House of the Dragon, based on George R. R. Martin‘s Fire & Blood book, officially started production this week. HBO revealed behind-the-scenes photos on Monday of the cast gathered for a socially distanced table read.

Set 300 years before the events of Game of Thrones, House of the Dragon will tell the story of House Targaryen.

Paddy Considine (The Outsider) will play King Viserys Targaryen, the successor of Old King Jaehaerys Targaryen, to sit on the throne of Westeros.

Olivia Cooke (Ready Player One) will play Alicent Hightower, daughter of the Hand of the King, Otto Hightower (Rhys Ifans).

Emma D’Arcy (Truth Seekers) will play Princess Rhaenyra Targaryen, a dragonrider.

Matt Smith (The Crown) will play Prince Daemon Targaryen, King Viserys’ younger brother whom Otto believes is a threat to his king.

Others in the main cast include Steve Toussaint (It’s a Sin) as Lord Corlys Velaryon, the lord of House Valaryon and a famed nautical adventurer known as “The Sea Snake”; Eve Best (Fate: The Winx Saga) as Princess Rhaenys Velaryon, a dragonrider and the wife of Corlys; Sonoya Mizuno (Ex Machina) as Mysaria, an ally to Daemon; and Fabien Frankel (Last Christmas) as Ser Criston Cole, a Dornish common-born son of the steward to Lord of Blackhaven.

Miguel Sapochnik and Ryan Condal serve as the new showrunners of House of the Dragon, which was created by Martin and Condal.

Game of Thrones composer Ramin Djawadi returns to score the new series.

This is but the first of many spin-off series that HBO is looking into to potentially develop after passing on a series order for the Naomi Watts-led prequel.