HBO's Game of Thrones prequel series The Long Night has cast Josh Whitehouse (Poldark) as its lead, though his character remains a mystery for now. Writer Jane Goldman and the rest of the team are currently casting in London, and this reveal follows closely on the heels of Naomi Watts being cast as a "charismatic socialite."

Set 8000 years before the events of Game of Thrones, The Long Night will explore the first time that Westeros was beset by a long and terrible, during which the White Walkers and their wight army descended on the weakened, freezing, and starving population. The series is expected to begin filming in early 2019, ready to take over the franchise after Game of Thrones' eighth and final season.

Related: Game of Thrones Theory: The Long Night Will Tell Azor Ahai's Story

Deadline reports that Whitehouse will play the lead role in The Long Night's pilot (which obviously doesn't preclude him being killed off at the end of season 1), but unlike with Watts, there are no details available as to what type of character he'll be playing. The show is set so far back in time that we don't know much about the world it's set in, other than stories about legendary figures like Azor Ahai and The Last Hero. Whitehouse could be playing either of those characters, or neither.

Whitehouse made his screen acting debut in the 2014 music drama Northern Soul, and also played young aristocrat Hugh Armitage in the historical drama series Poldark. This is an early indication that The Long Night will take a similar casting approach to Game of Thrones: mixing established actors (like Naomi Watts and Sean Bean) with rising stars. With two cast members revealed in quick succession, we'll likely see more names revealed as the week continues.

Deadline also offers an intriguing synopsis for The Long Night, which reveals that the prequel will unravel many mysteries that are present in the current series:

The untitled prequel takes place thousands of years before the events of Game Of Thrones. It chronicles the world’s descent from the golden Age of Heroes into its darkest hour. And only one thing is for sure: from the horrifying secrets of Westeros’ history to the true origin of the white walkers, the mysteries of the East to the Starks of legend… it’s not the story we think we know.

The reference to "Starks of legend" indicates that Whitehouse could actually be playing an early ancestor of the Starks, which would be an interesting way to maintain a connecting thread between the two shows. With Game of Thrones close to its end, it looks like a whole new age of speculation and anticipation has dawned.

More: How Game of Thrones Prevented Set Photos From Spoiling the Series Finale

Source: Deadline