Keira Knightley has very fond memories of one particular sex scene she was involved in.

In a new interview with Vulture, the 33-year-old opens up about shooting the sex scenes in her new film “The Aftermath” and looks back on another sex scene she did for the 2007 film “Atonement”

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“The best sex scene I’ve done on-screen is the one in ‘Atonement’, on the bookshelf,” Knightley said. “It was both the best sex scene, but also [the best] to shoot.”

The actress said shooting the scene was a great experience because director Joe Wright “choreographed the scene within an inch of its life. It was absolutely, ‘Foot goes up there, hand goes up there. So both me and James [McAvoy] felt utterly comfortable and not exposed, and like we could deal with it. It’s never gonna be fun, but we could deal with it.”

When it came time to do her scenes in “The Aftermath”, Knightley made sure director James Kent approached things the same way.

“What never helps is when a director goes, ‘Oh, you guys know what you’re doing.’ [And you’re like], ‘Uh, I’ve never met this person, I have no idea what I’m doing in this room full of men,’” Knightley said. “With sex scenes in particular, it always has to be choreographed like a dance. So with James [Kent], I was like, ‘You’re the director, you know what you want from this, so you have to just tell us. And everyone will feel comfortable.’”

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When asked about it, Kent credited Knightley for changing his entire approach to how he now films sex scenes.

“Keira asked me to narrate — [she said] otherwise, you’re too conscious that we’re doing it,” he said. “But if you narrate, it takes the awkwardness out of it, it becomes technical.’”