‘My Body Was Completely Different’: Sydney Sweeney Details Gaining Over 30 Pounds for Role

The 27-year-old had to transform in order to play boxer Christy Martin.

Sydney Sweeney on ‘The Kelly Clarkson Show’ / Weiss Eubanks/NBCUniversal/Getty Images

Sydney Sweeney remains booked and busy—and she’s proving she’s got major versatility. After scoring roles in popular TV shows like The Handmaid’s Tale and Sharp Objects, the Washington native landed her breakout moment with the smash-hit Euphoria. In the years since the first season, she’s appeared in blockbusters, indies and everything in between, while also producing projects under her company Fifty-Fifty Films.

It’s currently an exciting time for Sweeney, with several highly anticipated projects on the way. One of which is the untitled Christy Martin biopic, in which the 27-year-old actress will portray the history-making boxer. To play such an athletic, strong woman, Sweeney had to put in work at the gym, totally transforming from her usual appearance.

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A post shared by Sydney Sweeney (@sydney_sweeney)

For her recent cover story with W Magazine, Sweeney touched on the process of gaining muscle for the role, revealing she had to put on over 30 pounds. “I loved it,” she said of the experience. “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.”

“My body was completely different,” Sweeney added. “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. It was crazy! I was like, Oh my god.”

“But it was amazing,” she confirmed. “I was so strong, like crazy strong.”

And it wasn’t just her body that needed to be altered. For the part, Sweeney wore brown contacts and a brown wig, as seen in first look photos for the film shared last year.

“This story is so much bigger than just a film,” she wrote on Instagram after filming wrapped. “It’s a testament to resilience, survival, and finding the strength to keep fighting. I can’t wait for you all to see it—not only because I’m proud of the transformation and the work I’ve poured into it, but because Christy’s story deserves to be told.”

While Sweeney’s athletic build for filming was quickly transformed back to her usual figure for her next role—she had to lose the weight in just seven weeks, according to her W Magazine cover story—that didn’t stop internet trolls from noticing and commenting on her body. After paparazzi shots of Sweeney in a bikini circulated the internet last December, she received cruel criticism from body-shamers.

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A post shared by Sydney Sweeney (@sydney_sweeney)

But Sweeney wasn’t going to let the nasty body-shamers win. Instead, she took to Instagram to share a compilation of the comments, followed by epic footage and photos of her training to get into shape for the film.

While the biopic isn’t due out in theaters until the fall, Sweeney has already begun promoting the film in creative ways. On Sunday, June 8, she joined Martin at the Boxing Hall of Fame Induction Weekend of Champions in Canastota, N.Y., where she led the parade as the event’s grand marshal. The actress and retired athlete rode through the streets together, waving at fans.

Christy Martin and Sydney Sweeney at the Boxing Hall of Fame Induction Weekend 2025 / Ed Mulholland/Getty Images

“Martin put female boxing on the map in the mid-’90s,” director and co-writer of the biopic, David Michôd, shared with W Magazine. “She was the first woman fighter on the cover of Sports Illustrated and fought on the Mike Tyson undercard. Her husband was also her trainer, and then, after her success, he tried to murder her. Our film is a wild mix of inspiring underdog sports-world story and personal saga. Sydney trained her butt off to play the part. The beauty of Sydney is that she turned up to work every day with her tail wagging, ready to go. No matter how tough it was, she was like a ray of sunshine.”

The biographical film is due out later this year.

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