He said: "It's quite nice walking around, which will only happen for a few months before everyone's seen it, knowing. I know and no one else does. I know how it wraps up. Yeah, I think it's gonna be groundbreaking."
Kit - who married Rose in June last year - admitted that he won't be fully "satisfied" until he's watched the last episode.
Asked whether he was pleased with how the show comes to an end, he said: "It's a weird one to answer that, I can't really answer whether I'm happy or not.
"I don't think it's about happy or sad really. I'm satisfied with what they did, but I don't know whether I'll be really satisfied until I see it."
Kit also ruled out Jon starring in the prequel series, which stars Naomi Watts, and is the work of Jane Goldman and 'GoT' author George R.R. Martin.
Asked if it's a possibility, he said: "No. I can tell you that, no. I have nothing to do with the prequels. I hope it goes very well for them, and I can't wait to watch it."
-Bang! Showbiz