Ben Affleck's sex scenes with Sienna Miller ended in tears

Ben Affleck

Los Angeles: Sienna Miller was left shaking with tears running down my face after a marathon love scene session with her 'Live By Night' co-star Ben Affleck.

Affleck plays notorious gangster Joe Coughlin in the crime drama, which he also wrote and produced. Sienna features in the film as Emma Gould. For the film, Miller and Affleck had to shoot several intimate scenes.

"It's hysterical," Miller told eonline.com.

"Ben and I are like brother and sister, thank god, so there was no awkwardness. There was just a lot of stupid giggling. He's very professional - I am not, but he is. In that environment, it was a cool scene."

Even before she joined the cast, Miller knew her role was rather risqué.

"There was a montage in the script saying we did it everywhere: in the car, in the bar... I was like, 'That's an entire day of just love scenes! Okay. How do we do this?'" Miller said.

"Obviously, by the time nine hours of it has gone past, I was shaking with tears running down my face. I mean, I can't tell you - but you have to laugh. Ben is just professional. It is what it is."

At one point, Affleck instructed the movie's director of photography, Robert Richardson, to "keep rolling" so they could film the same sex scene "a few times" without having to cut.

"I was like, 'Okay, obviously Joe Coughlin is a real performer.' This happened three times, and by the third, I (finally said), 'Are you joking?'" the 35-year-old actress said.

"And then I was like, 'I don't know what you're trying to tell people, Ben, about your sexual prowess - your abilities.'"

"It turns out that he was just giving himself options without cutting," she added.

"But to me, it was the funniest thing. I was like, 'No one can do what you're doing, the marathon love scene.'"