Kit Harington could never work alongside his fiancé Rose Leslie again.

The 30-year-old actor starred alongside his future wife in 'Game of Thrones' but admits it would never happen again because he just ''wouldn't be able to keep a straight face'' around her on set.

He said: ''I wouldn't be able to keep a straight face. Honestly, I was watching Sliding Doors with her the other day, and there's a bit at the end where John Hannah is pouring his heart out to Gwyneth Paltrow and she's lying dead. I turned to Rose and I said, 'I wouldn't be able to do that with you, because you would piss yourself.' She's a brilliant actor. Actually I don't want to work with her because she would just show me up again. That's why.''

Kit recently moved in with Rose, 30, and absolutely loves sharing a house with his partner.

He added: ''Me and Rose, my girlfriend, said we need a few months together in London for some downtime. We've just moved in together. I've never lived with a partner before. It's amazing.''

However, Kit and Rose do have one rule - they will not both take photographs with fans when they are together as they want to make sure their relationship isn't ''defined'' by their characters.

He told The Times newspaper: ''The tough bit is when you are on holiday and people want photos with both of you. We don't do that, because there is a line where you go, 'Our relationship is not one of two puppets who are like walking advertisements.'

''So one of us will have a photo taken and the other will say no. That's important - that your relationship isn't defined by what you were as two characters in the past.''