Production has officially begun on House of the Dragon, HBO's first Game of Thrones spinoff series. After the parent series concluded last year, HBO has sought to expand the franchise by putting various prequels into production. Taking to Twitter on Monday, the cabler announced that the upcoming series House of the Dragon has started filming in the UK by releasing a behind-the-scenes photo of a table read. You can take a look at it below.

"Fire will reign," HBO writes in the caption, stating that House of the Dragon is officially in production. A prequel series, House of the Dragon takes place 300 years before the events of Game of Thrones. It is based on material from George R. R. Martin's Fire and Blood and will track the beginning of the end for House Targaryen. Ryan Condal (Colony) and Miguel Sapochnick (Game of Thrones) will serve as co-showrunners in addition to executive producing alongside Martin and Vince Gerardis. House of the Dragonwas co-created by Martin and Condal, with Condal writing the pilot script that landed the show its series order from HBO.

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Like Game of Thrones, House of the Dragon will feature an ensemble cast. The prequel stars Olivia Cooke (Ready Player One) as Alicent Hightower, Emma D'Arcy (Truth Seekers) as Princess Rhaenyra Targaryen, and Steve Toussaint (Prince of Persia: The Sands of Time) as Lord Corlys Velaryon, known as The Sea Snake, who becomes Hand to Rhaenyra during the Dance of the Dragons.

The series also stars Eve Best (Nurse Jackie) as Princess Rhaenys Velaryon, Rhys Ifans (Notting Hill) as Otto Hightower, Sonoya Mizuno (Crazy Rich Asians) as Mysaria, Fabien Frankel (Last Christmas) as Ser Criston Cole, Matt Smith (Doctor Who) as Prince Daemon Targaryen, and Paddy Considine (Peaky Blinders) as King Viserys Targaryen.

"[Considine is] just an incredible actor," Condal told Winter Is Coming last year. "Honestly, we didn't talk about anyone else, as soon as his name came up. He can do anything, you look at his body of work, and he's done everything from comedy to dark drama, he's an incredibly gifted actor. We know he can pull [off] anything that we give him to do."

Prior to the production of House of the Dragon, another planned Game of Thrones prequel had been in the works at HBO. Dubbed Bloodmoon and starring Naomi Watts as a "charismatic socialite holding a dark secret," the prequel series was set around 10,000 years before the events of Game of Thrones. After the pilot was filmed, HBO opted not to move forward with the series. Fortunately for House of the Dragon, it's already been given a 10-episode season order.

Just recently, fans celebrated the tenth anniversary of the first episode of Game of Thrones. As for House of the Dragon, the series will arrive in 2022 with an official release date yet to be revealed by HBO. It remains to be seen if the prequel will be as popular as the original series, at least before the show's final season. This news comes from Game of Thrones on Twitter.