According to reports, HBO is looking to produce another Game of Thrones prequel to the TV screens, this time adapting George R. R. Martin‘s Tales of Dunk and Egg.

The adaptation is currently in early development, sources state. There’s no info about writers or cast members yet, but it is supposedly “a high priority” for the network as it is aiming to “build on the success” of the original eight-season series.

Tales of Dunk and Egg is set 90 years before A Song of Ice and Fire, and follows Ser Duncan the Tall (Dunk) and a young Aegon V Targaryen (Egg). Martin has written three novellas in the series, namely 1998’s The Hedge Knight, 2003’s The Sworn Sword and 2010’s The Mystery Knight.

HBO is already working on the first Game of Thrones prequel House of the Dragon, which stars Dr. Who’s Matt Smith as Prince Daemon Targaryen, Emma D’Arcy as Princess Rhaenyra Targaryen and Olivia Cooke as Alicent Hightower. The upcoming series has a 10-episode order and is scheduled to premiere some time in 2022.