Game of Thrones' Nikolaj Coster-Waldau talks fan theories and show's 'sad-isfying' ending

With just days to go until Game of Thrones returns, and just a few weeks until it's gone for good, fans all over the world are trying to predict exactly how the hit HBO series will end. Well, star Nikolaj Coster-Waldau knows, and while he's not telling anyone, he did coin an interesting word for what to expect: "sad-isfying."

Coster-Waldau was on Jimmy Kimmel Live! Tuesday night to promote the upcoming final season of the fantasy epic in which he plays Jaime "The Kingslayer" Lannister, and host Jimmy Kimmel was eager to ask him just how much he knows about what's to come. Coster-Waldau didn't go the popular press tour route of playing dumb, confirming that he's known the ending for some time now, but he did take a little time to discuss the levels of secrecy he's been held to, including software that erases scripts from his device as soon as he's done reading them.

“We don’t have the scripts for Season 8. They don’t exist," Coster-Waldau said, noting that he has hard copies of his scripts from all of the show's other seasons. "It’s a little sad.”

With one of the show's biggest stars in his guest seat just days before the premiere, Kimmel decided to see what he could learn about the final season not by asking direct questions about the plot, but by posing various fan theories to Coster-Waldau to see how he'd react. To that end, Kimmel mentioned everything from the theory that Jaime will kill his sister Cersei — "It makes sense, though, if you think about it," Coster-Waldau said — to the theory that Arya Stark will kill Cersei while wearing Jaime's face, which Coster-Waldau acknowledged would be a "cool" resolution.

Then there were the less compelling fan theories, including the idea that Jon Snow will become the new Night King ("How?") and the idea that the Starks are descended from White Walkers.

"Many believe that to be the case," Kimmel said.

"OK," Coster-Waldau said while flashing a whatever-floats-your-boat smile.

Kimmel then asked Coster-Waldau if he'd read any fan theories and predictions that actually turned out to be correct, or which may still prove correct when we see the final season.

“Some, but I’ve never read anyone who got the whole thing," Coster-Waldau said, then went on to praise showrunners David Benioff and D.B. Weiss for somehow managing to take an extremely complex show and — in his eyes, anyway — stick the landing. According to Coster-Waldau, as soon as he'd finished reading the Season 8 scripts, he wrote to Benioff and Weiss to congratulate them.

“I don’t know how you did it, but I can’t imagine a better way of ending this show," he recalled telling them.

"Really? Oh, it's that satisfying?" Kimmel asked.

"It is," Coster-Waldau replied. "Sad-isfying. Yeah."

Anyone who's been paying attention knows that Game of Thrones has never been a show of happy endings. Even when the endings are happy, there's some kind of awful sacrifice characters had to make to get there, and the series finale will be no different. The Kimmel audience groaned when Coster-Waldau used the term, but when it comes to Game of Thrones, "sad-isfying" might be the highest praise anyone can give it.

Game of Thrones returns Sunday at 9 p.m. EST on HBO.