It may look steamy when on the big screen, but filming a sex scene with Brad Pitt in “Allied” was anything but for Marion Cotillard.

The pair play on-screen lovebirds in the spy thriller and get busy in the backseat of a car during a sandstorm at one point in the film.  Cotillard tells US Weekly that filming the scene took a lot of coordination and practice to make it look natural and sexy.

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“We rehearse and had a very determined choreography, and then it allows you freedom. When you know exactly what your body will do, then you can act and you can be free to give the emotions and give the feelings because you won’t think, What am I going to do next? Am I going to go on top of him? It’s an awkward situation,” she says.  “We laughed because you need to get it out because this is so weird. And so you get this time of looking at each other and saying, ‘OK, this is so weird. And then we go into this and then I’m going on top of you and then we are going to kiss.'”

The Oscar-winning French actress gave co-star Pitt some French lessons to ace the scenes in which his character speaks her native tongue.

“He had this commitment to do the best he could, which was really, really impressive, so I helped him by being very tough,” she explains. “I was very honest with him. But at the same time, I really wanted to support him in this process that I went through, and I know how hard it is.”

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Their on-set chemistry sparked rumours Cotillard was behind Pitt’s split from Angelina Jolie. The actress and her longtime partner Guillaume Canet quickly put speculation to rest as Cotillard publicly declared her love of Canet and announced she was expecting the actor’s second child.  She also sent her best wishes to Pitt and Jolie as they navigate through a “very tumultuous moment.”

Catch Cotillard and Pitt in “Allied” when it opens in theatres on November 23.