HBO developing a Game of Thrones prequel based on George R.R. Martin's fantasy novellas Tales of Dunk and Egg

Variety

The potential series would follow the adventures of Ser Duncan the Tall (Dunk) and a young Aegon V Targaryen (Egg) 90 years prior to the events of A Song of Ice and Fire. Martin has published three novellas in the Tales of Dunk and Egg series to date: The Hedge Knight in 1998, The Sworn Sword in 2003 and The Mystery Knight in 2010. No writer is currently attached.