Lena Headey in Game of Thrones

Helen Sloan/HBO

HBO is giving "Game of Thrones" a fitting farewell. A week after the series finale airs, the premium network will debut a two-hour feature documentary called "Game of Thrones: The Last Watch."

The documentary is directed by filmmaker Jeanie Finlay ("Seahorse"), who was embedded on the set while Season 8 was being filmed. It will give fans a unique window into the show's final season. As HBO describes it, "'Game of Thrones: The Last Watch' delves deep into the mud and blood to reveal the tears and triumphs involved in the challenge of bringing the fantasy world of Westeros to life in the very real studios, fields and car-parks of Northern Ireland."

The cast and crew have talked about what a grueling season this was to make, especially with its massive battle that took 55 nights to film. HBO highlights some of the challenges they faced, including "extreme weather, punishing deadlines and an ever-excited fandom hungry for spoilers." And on top of that, there was the emotion aspect of saying goodbye to the show.

Season 8 episodes will air weekly from April 14 to May 19 on Sundays at 9 p.m. ET/PT on HBO.  "Game of Thrones: The Last Watch" follows the next Sunday, May 26, at the same time.