Author George R.R. Martin told Liam Cunningham a secret about "Game of Thrones," but the Ser Davos actor isn't about to share it with anyone.

“This was a couple of years ago. It was the first time I met him, and I was awestruck," Cunningham recalled Thursday on "Conan." "He said, ‘I’ve got something to tell you.’ And he leaned in and he told me this secret. He said, ‘Don’t tell anybody.’ So I’m not.”

Don't expect him to reveal any spoilers about the upcoming sixth season of the hit fantasy drama, either. "“I’d love to tell you, but HBO has a person in the room here, and I don’t know where they are [...] a Barrett .50 sniper rifle,” Cunningham warned host Conan O'Brien. “If I open my mouth here tonight, I’m out of here. You could be taken out as well, for asking the question.”

He could, however, reveal a new clip from Season 6, in which the actor's Davos Seaworth, Ghost and a few others prepare to fend off the Night's Watch over the body of Jon Snow. “I’ve never been much of a fighter," Davos says as he draws his sword, "so apologies for what you’re about to see."

"Game of Thrones" returns Sunday, April 24, on HBO.