Kit Harington revealed the ending of Game Of Thrones to a friend who had not watch the series - because he felt he had to get it off his chest.
The actor, whose alter-ego Jon Snow edges ever closer to securing the Iron Throne, said he told his friend James, who had started watching the epic saga but fallen asleep during the first episode.
Harington, 32, said he was driven to divulge who would rule Westeros by the "intensity" of having to keep the show's ending a secret.
He told the Graham Norton Show: "The intensity of finishing something like this and not being able to tell anybody is so hard.
"It got too much, so I've told one person - my friend James, who doesn't watch the show and fell asleep in the first episode of the very first season.
"I knew then that he was zero-interested in what I do.
"We were having a drink the other night and I told him everything about how the series ends, and he couldn't have looked less interested if he tried."
Harington also admitted having anxiety dreams.
He said: "There are some incredible sequences, but I've woken up in the middle of the night recently thinking 'What if, after eight seasons, we have mucked it up?'."
Other stars have struggled to keep quiet about the show's ending, with Sophie Turner, who plays Sansa Stark, admitting her fiance, Joe Jonas, knows how it ends but is under strict orders not to spill any secrets.
The final series of Game Of Thrones begins on Sky Atlantic and NOW TV at 2am on Monday and is repeated at 9pm.