Emilia Clarke was shocked by Jason Momoa's replacement for modesty sock during sex scene

Emilia Clarke revealed she was left shocked by Jason Momoa's replacement for a modesty sock during a sex scene.

The two actors played Daenerys Targaryen and Khal Drogo in Game of Thrones and were in a number of pretty intense - and sometimes violent - scenes together.

Emilia Clarke revealed how Jason Momoa lightened the mood (HBO)

Keen to put his co-star at ease, Clarke - who turns 38 on Wednesday (23 October) - explained how Momoa pulled a few pranks to lighten the mood, including a pretty wild stunt with a modesty sock before a sex scene.

A modesty sock is a piece of clothing worn by actors to provide some modesty during filming nude scenes.

Clarke recalled her pal's hilarious prank during an appearance on The Graham Norton Show, explaining: "There was the lovely, erm, the lovely r**e scene early on in season one... so obviously, there's nudity and you kind of have to try to lighten the mood."

Clarke explained that instead of using a modesty sock, Momoa brought something quite different to filming.

"Not only was it a sex scene, it was a violent sex scene, so he decided for one of the scenes... not use a modesty sock, but use a beautiful pink, fluffy sock," she said.

Speaking of her shock, the actor added: "So, getting that close-up of me looking petrified, just like' I didn't want it to happen, it's huge and it's pink and I don't know what to do!'"

Momoa also opened up about his decision to ditch the modesty sock for a pink fluffy number.

During a Game of Thrones Q&A, he recalled the exact same incident, sharing: "I was in Belfast and it's December, and we're going to shoot and it's freezing and I'm the last one at Titanic studios.

Momoa used a fluffy sock instead (Frazer Harrison/Getty Images for AFI)

"It's cold... and I'm naked and I've got to walk into a room and show my ass and [Emilia] has to be looking at me, so I go in there and was like, 'Make this done... let's roll.'

"And I just wanted to get this done but the thing is, it was the only scene that was supposed to be in the very beginning and it got bumped, it got bumped, it got bumped and finally... I was the first one there, and I was the last f***ing thing to shoot.

"So I stayed there the whole time, but I shot the last scene of the whole thing. And I was like; 'I'm going to have some fun with this'.

"So I went down and bought a little bag of these socks. Some fluffy pink polka dot socks with little animals and I put it in... appropriate places. I look around and there are these grips walking around everywhere and I'm like, 'Whatever, it's like a locker room. It's all a part of making [Emilia] laugh.'"

Momoa continued: "I turn around and I'm walking towards her and am just doing ridiculous moves just to make fun of her close-up, and she's trying to hold it together, but she keeps laughing."

When the director called Clarke out for laughing, she cried out: "Jason has a fluffy pink thing on his... penis."