As the upcoming Game of Thrones prequel series continues to flesh out its core cast, now comes word on several new additions for the hotly anticipated Naomi Watts-headlined offering.

Courtesy of Deadline, we now have word that genre fave John Simm is leading this most recent batch of casting announcements, with the Human Traffic and Doctor Who star joined by Luke Cage’s Marquis Rodriguez, Collateral’s Richard McCabe, Brexit’s John Heffernan and relative newcomer Dixie Egerickx. In addition to the aforementioned Naomi Watts, the show already has Josh Whitehouse, Miranda Richardson, Denise Gough, Jamie Campbell Bower and Alex Sharp on board.

At this stage, there are no details whatsoever on just which characters any of these names are playing, and details of the prequel effort itself are being kept hush-hush for now. What we do know, however, is that Jane Goldman and George R.R. Martin have developed a story that is set thousands of years before Game of Thrones, with Goldman penning the series. Given the timeline of the prequel show, that means that no existing Thrones characters will be appearing.

If you remember, this is just one of several other Game of Thrones shows in development right now. The Goldman and Martin-crafted series is the only one with any cast in place right now, but a further three further prequel shows set in different periods are also in development.

As for Game of Thrones itself, the main show will return for its final season in only a matter of weeks.