Ben Affleck, who played the role of Joe Coughlin, a notorious gangster in the Warner Bros’ crime drama “Live by Night,” unintentionally made a reputation for himself on the set of the movie.

The 44-year-old Oscar winner also wrote and produced the film, which co-starred Sienna Miller as Irish vixen Emma Gould.

To bring Dennis Lehane’s popular novel to life, Miller and Affleck had to film several s^x scenes.

Miller knew her role was quite risqué even before she joined the cast, as there was a montage in the script indicating that the characters had s^x everywhere.

She said, “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! OK.

How do we do this?'”

Affleck’s directorial duties also required him to give Miller some acting notes while making her feel comfortable in an uncomfortable situation.

“It’s hysterical,” Miller told E! News anchor Maria Menounos.

“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.”

While filming the s^x scenes, Affleck asked the movie’s director of photography, Robert Richardson, to “keep rolling” so they could film the same s^x scene “a few times” without having to cut.

Miller found it amusing and 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.”

Miller laughed at Affleck’s stamina and remarked, “No one can do what you’re doing, the marathon love scene.”

At one point, Affleck instructed Richardson to keep filming even though Miller thought the scene was over.

“Sienna thought that I was trying to make myself out to be some kind of world champion, where it just never ended,” Affleck shared with Menounos.

“She started laughing and I was like, ‘Laughing isn’t really the response that I’m looking for with this.’ She was like, ‘How long can you go? You’re Superman!'”

Affleck, who found the whole experience amusing, admitted that he didn’t tell Miller ahead of time that he would keep filming.

He said, “The camera was still rolling.

“I didn’t tell her ahead of time, so she was taken a little off guard.

“I thought she’d just roll with it.”

Miller, on the other hand, couldn’t stop laughing at Affleck’s stamina.

“There will be some outtakes from that [scene] where I have to walk out of the room because I just have tears running down my face,” she shared.

“It turns out that he was just giving himself options without cutting,” Miller added.

“But to me, it was the funniest thing.

“I was like, ‘I don’t know what you’re trying to tell people, Ben, about your s^xual prowess—your abilities.'”

Affleck’s co-star, Chris Messina, also had some insights into the s^x scenes.

“It was like a five-minute s^x scene that ended up going for nine hours,” he joked.

Regardless, Miller praised Affleck for being professional throughout.

“Ben is just so lovely and kind and patient, and he never ever made me feel uncomfortable in any of those scenes,” she said.

“He’s a gentleman. He really is.”