The first Game of Thrones spinoff series may debut earlier than expected. HBO revealed earlier this year that they are working on expanding the core Game of Thrones series, with multiple spinoff shows currently in the works. They originally said they had four spin-offs in various stages of development, with Jane Goldman (Kingsman), Max Borenstein (Kong: Skull Island), Brian Helgeland (Legend) and Carly Wray (The Leftovers) shepherding the projects. Then, last week, the network tasked series writer Bryan Cogman to helm a potential fifth GoT spinoff.
However, the network doesn't expect all of these new Game of Thrones projects to go to series, nor even reach the pilot stage. So far, all we know is that the spinoffs most likely won't focus on stories that are directly related to the core Game of Thrones characters, such as the tale of Robert's Rebellion (mostly because we know how those stories play out). Still, with a world like the one that George R.R. Martin created, there are numerous possibilities of where to take the small screen franchise next. Of course, aside from plot details, many people would like to know when the first spin-off will debut, and it might be sooner rather than later.
Shortly after it was announced that Cogman had been hired to develop another potential Game of Thrones TV series, Martin took to his Facebook page to praise the writer, who he says has been working on the spinoff for months but could only now reveal the news. Furthermore, he says that the first spinoff could come as early as 2019 or maybe even 2020.
"You should not expect to see all five shows, though, at least not immediately.. much as I might love the idea, HBO is not about to become the GAME OF THRONES network... but we could possibly see two or even three make it to the pilot stage, with one series emerging on air in 2019 or 2020... and the others maybe later, if they come out as well as we all hope."
Considering that HBO's flagship series may not end until 2019, if the core series' producers aren't able to air season 8 in 2018, then that means the network may have one Game of Thrones show end and another begin in the same year. Since they now have five shows in development, it's reasonable that HBO would like to have Game of Thrones air year-around going forward, similarly to how AMC attempts to do just that with The Walking Dead and Fear the Walking Dead. However, as Martin says, HBO doesn't want to suddenly become the Game of Thrones network.
So, while it's unlikely that all five shows will make it to series, Game of Thrones book and series fans may take as many Westeros-related shows as they can get, so long as the quality of the spin-offs resemble the core series that people have come to know and love.
Source: George R.R. Martin