HBO has begun filming its untitled Game of Thrones prequel series. Based on George R.R. Martin's A Song of Ice and Fire novels, Game of Thrones premiered on HBO in 2011 and only just finished its eighth and final season in late-May. The show's last season was incredibly popular in terms of ratings, but struggled to impress critics - who took the season to task for its rushed pacing, unearned narrative payoffs, and dazzling yet hollow spectacle - and continues to be heavily debated and/or discussed by general viewers online almost a month after its finale aired.

But of course, from a brand perspective, Game of Thrones is still in tip-top shape, and HBO intends to tap into that with the upcoming prequel series. Writer-producer Jane Goldman (who's long served as filmmaker Matthew Vaughn's writing partner) is serving as showrunner on the series, which itself will take place thousands of years prior to the events from Game of Thrones proper. According to the official synopsis, the show will explore its setting's "descent from the golden Age of Heroes into its darkest hour" and reveal the "horrifying" truth behind Westeros' history, including (but not limited to) the "true origin of the white walkers".

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According to EW, filming is now underway on the Game of Thrones prequel show (which is currently going under the working title Bloodmoon). The series is shooting around Northern Ireland, which is also where Game of Thrones' main production was based throughout its run. That should help to maintain a sense of continuity between the two TV series, as far as what Westeros itself looks like.

The Game of Thrones prequel pilot is being directed by S.J. Clarkson (Jessica Jones), and features a cast led by Oscar-nominee Naomi Watts as the series' protagonist - a "charismatic socialite hiding a dark secret", according to a previously-released description. Other cast members confirmed so far include Naomi Ackie (who's also costarring in this December's Star Wars: The Rise of Skywalker), as well as Jamie Campbell Bower (Mortal Instruments), Denise Gough (The Witcher 3: Wild Hunt), Miranda Richardson (Good Omens), and Josh Whitehouse (Poldark), among others. So far, however, details on who, exactly, they're planning and/or their possible connections to Westeros' most famous families are being kept firmly under-wraps.

As far as its premiere goes, the Game of Thrones prequel could plausibly be ready to start airing as soon as the second half of 2020. Thing is, though, HBO has typically debuted its biggest genre shows in the spring (Game of Thrones specifically), and is expected to carry that tradition over into 2020 by releasing Westworld season 3 during that frame. And seeing as the latter only premieres a new season every two years, that creates an opening in HBO's schedule in Spring 2021 that Goldman's prequel should be able to fill nicely. Besides, after Game of Thrones' controversial eighth season, fans could probably do with an extended break from the property to cool off a bit.

NEXT: What to Expect From the Game of Thrones Prequel Show

We will let you know when the Game of Thrones prequel gets an official title and/or premiere date.

Source: EW