HBO has confirmed details of a new "Game of Thrones" prequel called "House of the Dragon."

The cable network announced Tuesday that it has ordered 10 episodes of the spinoff series based on George R. R. Martin's companion book "Fire & Blood."

Taking place 300 years before the events of "Game of Thrones," the series will depict the stories of the Targaryen kings who had long ruled Westeros.

Miguel Sapochnik and Ryan Condal will partner as showrunners, according to the premium cable channel, with both also poised to work as executive producers alongside Martin and Vince Gerardis.

"The 'Game of Thrones' universe is so rich with stories," Casey Bloys, president of HBO programming, said in a statement.

"We look forward to exploring the origins of House Targaryen and the earlier days of Westeros along with Miguel, Ryan and George."