We also know that Thrones showrunners David Benioff and D.B. Weiss are out of any continuation of the franchise, and that Martin himself is already busy with two of the four prequels that were already announced, while who else is involved has been as mysterious as the prequels themselves.
Cogman has worked in several roles on the original HBO series, including as a writer and a co-executive producer.
Game of Thrones writer Bryan Cogman will be working with George RR Martin in order to bring the Game of Thrones spin-off forward.
"I immediately fell in love with the book from page one, as most people do", Cogman said in a 2011 interview with The Westeros.org.
"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".
He joins Brian Helgeland, Carly Wray, Jane Goldman and Max Borenstein for the top secret projects. With the show's going back in time and Cogman being unofficially dubbed the "lore master" in the writer's room, it is quite the coup to have him on board.
Given their affinity for all things GoT, the smart money is on HBO running with the show co-created by Cogman and Martin first.
So at this point we do know what these new series are not about, and we know they will take place before the events of Game of Thrones. While Game of Thrones fans are still in shock following the Season Finale of Season 7 of the TV show, they were even more so after the announcement of the release date of the sequel.