'A Knight of the Seven Kingdoms,' the newest 'Game of Thrones' prequel, is on the horizon. Here's what to know about it.

Peter Claffey and Dexter Sol Ansell as Dunk and Egg in "A Knight of the Seven Kingdoms."

Steffan Hill/HBO

• HBO is expanding the "Game of Thrones" universe with another prequel series.
• "A Knight of the Seven Kingdoms" takes place between the main series and "House of the Dragon."
• It's based on George R. R. Martin's novellas that follow a hedge knight, Dunk, and his squire, Egg.

"House of the Dragon" season three probably won't air until the summer of 2026, but...