The actress strips off for a sex scene with Joaquin Phoenix at the beginning of the film.

Mendes told Fox News: "The sex scene with Joaquin really wasn’t as good as it looked - these were nerve-racking scenes that are very technical and really scary.

"It was nothing to do with him, he is beautiful, but when you are exposing yourself emotionally and physically that’s so frightening...you have so many people around and the camera and it’s so scary.

"It premiered in Cannes and I'm sitting there in the audience and I was like, 'Oh my God, no that's me. Oh my God, oh my God. That's me. That's my boob, that's my boob'."