And his horrific April Fool’s joke nearly ended his relationship with fiancée Rose Leslie, he reveals.
Kit, 30, who plays Jon Snow in the hit TV series, explained the prank on the Jonathan Ross Show.
Kit revealed that he hid a severed head, that looked identical to his own, in the fridge of their home for Rose to find.
The Scottish actress’ reaction was captured on camera, as the English star filmed her discovering the grisly prop.
He told the host: “My family does April Fool’s. Her family doesn’t do April Fool’s. After [the prank] she was in tears. And I was there going, ‘April Fool’s!’
“It didn’t go down well. She pretty much told me if I did it ever again, that would be it, and I think that’s marriage included.”
Last month Kit and Rose, 30, who have been dating since meeting on the set of Game of Thrones in 2012, announced they were engaged through a notice in a British newspaper.