One of Sydney Sweeney's latest roles required her to look nothing like Sydney Sweeney, star of The White Lotus and Euphoria.

"My body was completely different," Sweeney said of training to play boxer Christy Martin in an upcoming biopic, during an interview with W.

“I didn’t fit in any of my clothes. I'm usually a size 23 in jeans, and I was wearing a size 27. My boobs got bigger. And my butt got huge," she described of the unexpected changes. "It was crazy! I was like, 'Oh my God.' But it was amazing: I was so strong, like crazy strong."

The actress was a fan of the physical transformation she made to play the phenomenally successful athlete, who boxed professionally from 1989 to 2012. Martin had a staggering 49 wins, with only seven losses and three draws to her name.

"I loved it," Sweeney said of the hard-core preparation required of her to fill the role. "I came onboard to play Christy, and I had about three and a half months of training. I started eating. I weight-trained in the morning for an hour, kickboxed midday for about two hours, and then weight-trained again at night for an hour."

The actress has always been active, just not quite this much.

"My mom told me from a very young age to fall in love with as many things as possible," Sweeney told the magazine. "And so I did fall in love, again and again: I love sports. I love being outside. I was on the ski team, and I wakeboarded. I slalom ski on water. I was on the soccer team and the softball team. And then my parents got me into grappling, which is like wrestling, and kickboxing. I was the only girl at the dojo. I trained there from 13 until about 19. I fought all guys. I liked to think that if s--- went down, I might be able to step up."

More was required than just physical preparation, as Martin faced strife at home too. After marrying her coach, Jim Martin, in 1991, he attempted to murder her in 2010. He was convicted of attempted second-degree murder in 2012. Martin went on to wed a former boxing rival, Lisa Holewyne.

Sweeney previously declared that she was "proud of the transformation and the work I've poured into it," although she noted that people had made harsh comments about her temporary appearance.

People accused her of looking "quite frumpy" and having "a horrible body," among other things. Sweeney responded with a video that showed her lifting weights and even training in the ring.