UPDATE (June 19, 2019): The Game of Thrones prequel has officially begun filming.
As pointed out by the Belfast Telegraph, shooting has started in Northern Ireland, a location familiar to fans of the show considering many scenes from the original series took place here. Reports have also noted that shooting sites across the province of Belfast were set up last week.
The prequel is from showrunner Jane Goldman (X-Men: First Class) along with author George R.R. Martin and director S.J. Clarkson (Jessica Jones). The show will be set thousands of years before the events in GoT and will follow the world’s “descent from the golden Age of Heroes into its darkest hour,” a description reads.
HBO previously stated Naomi Watts will play “a charismatic socialite hiding a dark secret” and will be joined by Naomi Ackie, Denise Gough, Miranda Richardson, Josh Whitehouse, Jamie Campbell Bower, Sheila Atim, Ivanno Jeremiah, Alex Sharp, and Toby Regbo.
Although no official premiere date has been shared, the series won’t likely air until 2021. Find more info below.
UPDATE (May 22, 2019): It was only a few months ago that HBO announced the official Game of Thrones prequel cast. However it looks like fans will need to wait until 2021 before the first episode airs.
Sitting down with Deadline, HBO programming president Casey Bloys hinted at the potential debut date. “Shooting a pilot in June (2019) and having it on the air a year later feels a little rushed, but it’s too soon to tell,” he stated. “The casting was completed a couple of weeks ago.” Bloys continued. “They are busy in Belfast prepping and getting ready to start shooting in a couple of weeks.”
Bloys also went on to clarify upcoming potential GoT spinoffs citing, “I certainly do not want to overdo it. We have so many varied shows coming up in  and ’20 and even into ’21. I think Game of Thrones is a fantastic property but I don’t want to just be the home of prequels and sequels and all that stuff. I think you want to be really careful about how you do it. That’s why we’ve been working on the Jane pilot for a long time, because we want to do it right. I don’t want to rush anything out just to rush it out. I think the last thing fans would want, something that was rushed out just to make it to air.”
Set to take place thousands of years before the events of Game of Thrones‘s current storyline, the forthcoming prequel will star Naomi Watts and Josh Whitehouse along with a bevy of newcomers such as Jamie Campbell Bower and Toby Regbo who both played younger versions of Grindelwald and Dumbledore in Fantastic Beasts: The Crimes of Grindelwald. The cast will also include Georgie Henley, Ivanno Jeremiah, Naomi Ackie, Denise Gough, Sheila Atim, and Alex Sharp.
The Game of Thrones prequel will take a closer look at the origins of the White Walkers, the mysteries of the East, and the Starks of legend.
In related news, unfortunately the Game of Thrones series finale was blocked in China due to Trump’s trade war.
Set to take place thousands of years before the events of Game of Thrones‘s current storyline, the forthcoming prequel will star Naomi Watts and Josh Whitehouse along with a bevy of newcomers such as Jamie Campbell Bower and Toby Regbo who both played younger versions of Grindelwald and Dumbledore in Fantastic Beasts: The Crimes of Grindelwald. The cast will also include Georgie Henley (Chronicles of Narnia), Ivanno Jeremiah, from Black Mirror‘s “Shut Up and Dance” episode, Naomi Ackie (Lady Macbeth), Denise Gough (Colette), Sheila Atim (Harlots), and Alex Sharp (To the Bone).
The Game of Thrones prequel will start shooting in early 2019 and will take a closer look at the origins of the White Walkers, the mysteries of the East, and the Starks of legend.
For more on HBO’s hit series, new Game of Thrones clip shows Daenerys arriving in Winterfell.