Speaking to The Wrap, the Game of Thrones star recalled an especially demanding shoot in which she performed choreographed intimacy scenes for hours with three male co-stars, resulting in the injury.

Her co-star Haley Lu Richardson later confirmed the incident, noting Clarke’s slight frame made her more vulnerable.

In Ponies, Clarke and Richardson play widows of Central Intelligence Agency operatives who return to Russia to uncover the truth behind their husbands’ mysterious deaths. Clarke’s character, Bea, must also seduce a senior intelligence officer, requiring multiple intimate scenes. Clarke admitted it was awkward to explain to a doctor that the injury happened while filming repeated sex scenes.