Liv Tyler drugged Kit Harington on first flight together

Liv Tyler drugged her Gunpowder co-star Kit Harington when they met for the first time on a plane.

The actress switched seats with the passenger sitting next to the Game of Thrones star in a bid to get to know him better ahead of their new film - but he slept for most of their seven hours together after Liv slipped him a Xanax anti-anxiety pill.

"We met on a flight but it was quite bizarre," Kit tells chat show host Jonathan Ross. "Liv sweet talked the guy that was supposed to be sitting next to me out of his seat so she could sit next to me on the flight. It was quite charming."

But the actor accepts the flight could have been a disaster for the two stars, adding, "We’ve got a seven hour flight ahead of us; if this is a nightmare then we’ve got two months on set which isn’t going to go so well. We did get on. And then she drugged me. She literally slipped a Xanax in my drink."

Liv tells the host, "No I didn’t! It was one of those weird flights, so you’re kinda not tired. I had some Xanax which I take - I’m a little bit nervous flying and with jetlag and traveling all over the world... So I said, 'Do you want a Xanax?' thinking he knew what it was and he was like, 'Yeah'.

"I thought I was doing him a favor. I said, ‘It’ll just help you sleep'."

But Kit passed out for several hours and woke up just before the plane landed.

"He woke up like, 'Where am I? What did you give me?'"

The Gunpowder co-stars' chat with Ross will air on his show in Britain on Saturday night (07Oct17).