"Game of Thrones" is going to film a prequel, and the screenwriter of "The New Batman" will join

HBO is working with Batman writer Mattson Tomlin on a series called The Conquest of Westeros, which is expected to be a spinoff of Game of Thrones.

Tomlin was involved in the writing of "The Batman" but was not credited in the end credits; he is currently working with director Matt Reeves to write the sequel script. In addition, he is also one of the screenwriters of the movie "Undead Army" starring Keanu Reeves.

"Conquest of Westeros" is described as a "direct prequel" to "House of the Dragon". The story will focus on the process of the Targaryen family, led by Aegon Targaryen, conquering the continent of Westeros.

So far, HBO has launched one Game of Thrones spin-off, House of the Dragon, and the next spin-off, A Knight of the Seven Kingdoms: Duncan and Egg, will begin filming this year.

HBO is also rumored to be considering a "Jon Snow" series featuring Kit Harington returning to star, as well as at least one animated series. But importantly, these projects, including "Conquest of Westeros," are currently only in the potential development stage and have not yet been officially confirmed.

Novelist George R.R. Martin said earlier this year that he didn't know if any of the "Game of Thrones" projects in development would actually be made and broadcast. Even if HBO decides to make a pilot, there is no guarantee that the show will eventually be seen by the audience. After all, HBO previously spent $30 million to shoot a "Game of Thrones" spin-off pilot called "Blood Moon", but it was not aired in the end.

Game of Thrones creators D.B. Weiss and David Benioff are currently developing a completely different type of series for Netflix as part of their $200 million partnership deal with the streaming service.