Sienna Miller had 'zero chemistry whatsoever' with Ben Affleck in Live by Night

Sienna Miller had "zero chemistry" with Ben Affleck on the set of their 2016 movie Live by Night.

During an appearance on The Drew Barrymore Show on Wednesday, host Drew asked the Anatomy of a Scandal actress about her favourite film co-stars.

Sienna admitted that she enjoyed working with many actors, including Bradley Cooper and Jimmy Fallon, but found it difficult to pretend to be in love with Ben while filming the crime drama.

"I'm close with Bradley (Cooper), I've worked with him twice, I love him," she began. "But Ben Affleck was like my brother. I've never laughed so much in my life. I mean that sounds like a ridiculous thing to say and like a name-dropping thing to say, but I actually mean it."

Sienna went on to explain that Ben, who also served as director on the film, had to carefully frame the shots as they have such different body shapes.

"We had zero chemistry whatsoever, it was hysterical. We were supposed to be in love, we could not be less attracted to each other. Which was hysterical," the 40-year-old smiled. "He has an enormous head, I have a small one, so they'd have to like put me slightly ahead of him... and he directed the movie and I could barely look at him for laughing the whole time."

Elsewhere in the conversation, Sienna confirmed she is in a relationship, and admitted that she is confused by the way in which people can "casually date" in the U.S.

"Like if you kiss someone in England, you're basically together," she added. "Like this whole 'I'm dating a few people' thing I'm like, 'What is (happening) like, how does anyone even manage that?!'"