KIT Harington has revealed the Game Of Thrones cast and crew filmed a secret episode that will never be shown on TV.

The actor starred in a pilot that wasn't used and the creators regularly threaten to embarrass him by releasing it, The Sun reports.

In a new interview, the star, who plays Jon Snow in the series, revealed he appeared in a pilot episode of the show before it was commissioned.

Harington, 30, admits TV bosses "made a lot of mistakes" and the footage was canned.

But they are keeping hold of the episode and he hopes the embarrassing video never gets released.

He told The Guardian: "They made a lot of mistakes. It didn't look right, didn't feel right, had nothing different about it.

"They say, if I ever p**s them off too much, they'll release it on YouTube.

"Every now and then, they send me a screengrab, just as a threat."

At the end of last series, Jon bedded Mother of Dragons Daenerys Targaryen, but is yet to find out she is actually his aunt.

Harington added that he hopes Jon has a funny reaction to the news he had sex with a relative.

He joked: "I really hope that he just nods slowly and goes, 'Damned right'.

"Something really horribly inappropriate, and you find out Jon's had a really sick mind the whole time.

"That's the way I'd love to play it. I'll try it for one take, anyway."

Harington recently revealed he's started work on the eighth and final season of Game of Thrones, and he cried when he read the script.

During an appearance on The One show, he said: "I cried at the end! It wasn't anything particular that happens.

"You have to remember, I've done eight years of it. I think, no one really cares about [Game of Thrones] more than us."

This story originally appeared in The Sun and is republished here with permission.