Olivia Cooke can deliver a punch. 

The actress, 31, once slapped her House of the Dragon co-star so hard, it made him cry. 

Cooke, who stars as Alicent Hightower in the Game of Thrones prequel, recalled the incident while promoting her new drama The Girlfriend. 

The slap was to take place in a scene with Tom Glynn-Carney, 30, who plays her sniveling son, King Aegon Targaryen.

Glynn-Carney encouraged her to slap him ‘for real’ so the two consulted with the stunt coordinator and got permission to go for it. 

‘I walloped him!’ she told The i Paper. 

‘I didn’t realize my own strength! It was a slap that echoed throughout the land and made him cry! It was the reaction he wanted for the cameras, but I felt terrible.’

Olivia Cooke can pack a punch. The actress, 31, once slapped her House of the Dragon co-star so hard that it brought him to tears. Pictured in London, June 2024

‘It was hideous,’ the Slow Horses actress said, adding, ‘I’ve always felt sick and wanted to cry after doing any stunt work like that.’

Cooke, now working on season three of the acclaimed series, discussed on The Tonight Show with Jimmy Fallon on Monday how she auditioned for months before receiving the call in 2020 that she had secured the role of Alicent.

‘My phone was plugged in by the wall, so I ended up crouching in the corner of my apartment while all my agents were on the line, saying, “Your life’s about to change, baby!”‘

‘I just felt immediate dread,’ she revealed, ‘because then you have to do it, don’t you? It felt like a gargantuan job.’

For The Girlfriend, Cooke had to work up the courage to appear in multiple sex scenes with her on-screen boyfriend, played by Laurie Davidson, 33. 

She told Fallon the two connected by singing karaoke. ‘I was like, “I know what will break the ice. Celine Dion, All Coming Back To Me Now.”

She said she and Davidson sang the seven minute song looking into each others eyes the whole time. 

‘Bless him. He didn’t know the song, but he harmonized perfectly, ’cause he was in Cats.’ 

‘I walloped him!’ she recounted to The i Paper about her scene with Tom Glynn-Carney, 30. ‘I didn’t know my own strength!… It made him cry! That was the reaction he wanted for the cameras, but I felt terrible.’

During her Monday appearance on The Tonight Show Starring Jimmy Fallon, Cooke shared how she auditioned extensively for the role of Alicent Hightower, only to feel ‘immediate dread’ afterward.

‘Because then you have to do it, don’t you?’ she  explained. ‘It felt like a gargantuan job’

 She and Davidson navigated the steamy parts on set with the help of intimacy coordinators.

‘It’s amazing to me that people had to just fudge their way through those scenes before those people existed,’ she told The i Paper.

The situation can be difficult for anyone, especially young actors who ‘don’t have the vocabulary to say what they’re not comfortable with. And for women, who’ll often get labelled ‘difficult’ or ‘a b**ch’ for speaking up.’

Robin Wright, 59, stars as Davidson’s mother in the series based on the Michelle Frances novel by the same title.

Wright not only stars in the six-episode series, but directed it as well. ‘Her job was so hard,’ Cooke told the outlet. 

Cooke made the comments why promoting her new series The Girlfriend, debuting on Prime Video on Wednesday

She stars with Robin Wright, 59, as the mother of her boyfriend, played by Laurie Davidson, 33. The role required Cooke to buck up her courage to act in steamy sex scenes with Davidson

Wright directed several episodes of the series. ‘She just loves it. It’s her calling,’  Cooke said;  Pictured in London on September 2

‘I’d see her finish a really dramatic scene, weeping. Then dash off to check the monitor and rush to the editing suite to see what else was needed,’ she shared.

Cooke said Wright ‘would tell you she would rather be a director than an actor at this point. She just loves it. It’s her calling.’

‘For a lot of actresses of her generation the only way into the industry was by starting out in front of the camera. Getting behind it to direct was almost unheard of, it was such a male enterprise.’

The Girlfriend debuts on Prime Video Wednesday September 10.