The Aegon's Conquest Game of Thrones spin-off is being developed both as a HBO TV show and as a "mammoth Dune-sized feature film"

The Game of Thrones spin-off focused on Aegon's Conquest might be a blockbuster film, or it might be a HBO show.

That's according to The Hollywood Reporter, which says the project "is being developed by HBO as a possible drama series and by the Warner Bros. film team as a mammoth Dune-sized feature film."

Aegon's Conquest refers to the very first King Aegon, who took Westeros with the help of his sister-wives, Rhaenys and Visenya, 100 years before the events of House of the Dragon and 300 years before the events of Game of Thrones. They conquered six of the seven kingdoms, with Dorne retaining its independence until much later.

In House of the Dragon, it was revealed that Aegon undertook his conquest because he foresaw the end of man thanks to a winter from the North, and a Targaryen would need to be seated on the Iron Throne to bring the Seven Kingdoms together to face the threat. This prophecy is called the Song of Ice and Fire, which is the name of George R.R. Martin's series of novels.

The Aegon's Conquest spin-off was first reported to be in development with The Batman 2 writer Mattson Tomlin attached back in 2024. However, updates since then have been non-existent.

Naturally, this spin-off would feature plenty of dragon action – the trio rode the massive dragons Vhagar, Meraxes, and Balerion – so it would make sense for this particular idea to become the first Game of Thrones movie. But, House of the Dragon and the later seasons of Game of Thrones have already proved that HBO can handle bringing fire and blood to the small screen, too.

In the same report, THR also reveals that the scrapped Jon Snow sequel series might be back in development, too – and, this time, it could end up featuring Arya Stark and be set in Essos.

Next up for Westeros is A Knight of the Seven Kingdoms, which arrives on January 18 on HBO in the US and January 19 on Sky/NOW in the UK. House of the Dragon season 3 is also coming this year.

For more, check out our guide to all the upcoming Game of Thrones movies and TV shows, or read our four-star A Knight of the Seven Kingdoms review.