House of the Dragon star Olivia Cooke reveals co-star's terrified reaction to seeing her pubic hair choice

Filming sex scenes can be very awkward, so some celebrities like to pull a prank on their scene partner to lighten the mood.

Sex scenes have been going on in movies and TV shows for decades, and I can imagine that they don't get any easier for even the most experienced of actors.

One movie star that has spoken out about filming intimate scenes is Sienna Miller, who said that she had a 'nine-hour' sex scene with her Live By Night co-star Ben Affleck.

While Miller insisted that there was no awkwardness between her and Affleck, she did say she ended up laughing at certain moments, so much so she had to talk off set in tears.

Meanwhile, Olivia Cooke played a prank on her House of the Dragon co-star Fabien Frankel during one of their sex scenes.

Olivia Cooke and Fabien Frankel played lovers in House of the Dragon (Marc Piasecki/WireImage)

Cooke stars as Alicent Hightower in the Game of Thrones spin-off, while Frankel portrays Ser Criston Cole. The pair begin a sexual relationship in the HBO show's second season.

Ahead of the release of season three – which premiered in the US one June 21 – Cooke was a guest on The Claudia Winkleman Show.

"I had to do a sex scene where my scene partner was underneath my skirts. You can imagine what was happening," Cooke, 32, explained to Winkleman and the other guests.

"We have to wear these sort of padded, sticky jock straps for, you know, obvious reasons. And I said, 'Can you make me the biggest hairiest merkin? And I want the colour to be fiery red to match my hair.'"

The actress admitted that she felt a bit bad after playing the prank (BBC)

"It looks incredible," she went on. "I stuck it on, and the reaction that my cast mate had, Fabien – I was a bit alarmed. I was like, like, 'Surely you’ve seen pubes before?'"

Apparently Frankel 'leapt to the other side of the room' and thought the merkin was actually real.

After seeing how 'shocked and disgusted' he was, Cooke went on to regret playing the prank on him.

"I was like, 'Oh no, what have I done? What have I done? I thought this was going to be funny.' But I think he was really stricken with anxiety from that experience."

Whoops.

Olivia Colman has done a similar thing in the past and played a prank on her The Favourite co-star Emma Stone during an intimate scene involving their characters.

In the scene, Stone has to 'finger' Colman (as she put it), so she put a sponge between her legs.

What Stone didn't know is that Colman purposely wet the sponge to give the La La Land star the fright of her life.

"Her face was a picture," Colman recalled to Graham Norton on his show. "She was going up my leg and she went 'urgh!'"

Maybe this is the type of prank all actors named Olivia play on their co-stars...