HBO Confirms Game Of Thrones Prequel Will Begin Filming Soon Big news on the way for Game of Thrones fans. HBO has announced filming of the Game of Thrones prequel, House of the Dragon, is set to start in April. The 10-episode series, starring British actor Paddy Considine as King Viserys Targaryen, will tell the story of the Targaryen civil war that took place about 300 years before the events portrayed in GOT. No official timeline yet on when the episodes could actually be released. Do you like when shows/movies do prequels? What do you hope to see in House Of The Dragon?