HBO on Thursday confirmed speculation that its hit show Game of Thrones won't return for its final season until 2019.

"It's official: @GameOfThrones will return for its six-episode, eighth and final season in 2019," HBO wrote on its public relations Twitter account Thursday afternoon.

Crews were still filming the show's final season as of late December, Deadline reported.

HBO said in a news release Thursday that David Benioff, D.B. Weiss, David Nutter and Miguel Sapochnik will direct the new episodes, alongside writers that include Benioff, Weiss, Bryan Cogman and Dave Hill. Benioff, Weiss, Carolyn Strauss and Frank Doelger will be the show's executive producers. Bryan Cogman, Guymon Casady, Vince Gerardis and series author George R.R. Martin will serve as co-executive producers.

Also on Thursday, Syfy confirmed it ordered another series based on a Martin-penned book, Nightflyers. Martin will not work on that project because of the exclusive nature of his HBO contract.

In an interview published by Deadline in DecemberKit Harington, who plays Jon Snow on the show, said he felt an added pressure in working on the last season.

"I think there's a certain pressure I've not felt before," Harington said. "Whereas before, every year there's always been a bit of pressure, this season is one where we could easily let people down."

But Harington qualified that statement by saying production was "going really well."

"These days are long and a grind but we've got the first section out of the way, and all is well," Harington said. "All is good."

By Sam Howard,

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