Sydney Sweeney reveals 30-pound weight gain for boxing biopic: “My b**bs got bigger. And my b*tt got huge”

Sydney Sweeney is gearing up for the release of her upcoming movie, where she plays the legendary boxer Christy Martin in a still-untitled biopic. Despite the details of the project still being under wraps, the actress shared an insight into her preparation for the role, including her rigorous training and how she gained weight for of it.

In an interview with W Magazine, published on Monday, June 9, 2025, the Euphoria star revealed that she gained 30 pounds from months of intense training for the role. She said:

"My b**bs got bigger. And my b*tt got huge. It was crazy! I was like, 'Oh my god.'"

However, it was all "amazing," according to the actress, adding that she became "crazy strong" because of the training. According to IMDb, the Christy Martin biopic is done filming and is currently in post-production.

Also mentioned in the W Magazine interview was that Sydney Sweeney had to drop the weight she gained for the biopic in "only seven weeks" as she prepared for her next project.

While the interview didn't specify what the next project was, the actress has several shows and movies in the pipeline.

She's going to return as Cassie in Euphoria and has the movies Echo Valley, The Housemaid, and Split Fiction.

Sydney Sweeney shares her training regimen for the Christy Martin biopic

Sydney Sweeney said that when she went on board for the project to play Christy Martin, she only had around three and a half months of preparation and training for the role. Sweeney added:

"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."

As Sydney Sweeney admitted to W Magazine, she gained 30 pounds for the upcoming movie, adding that her body was "completely different." Her usual clothes didn't fit anymore, and while she was a size 23 in jeans before the training, she ended up wearing a size 27 during that time.

The actress shared the first photos of her transformation to play Christy Martin in the biopic last year.

In her October 16, 2024, post on Instagram, she shared a picture of herself sporting a mullet and another one of her flexing her biceps. In the caption, she wrote:

"Well the cat's out of the bag thanks to some paps in bushes so here's a little bts from my film I'm working on right now. Over the past few months, I've been immersed in training to bring to life the story of an incredible woman."

She went on to talk about Christy Martin being a "true champion" for her "resilience, strength, and hope."

Sydney Sweeney also shared a montage of herself in the gym, working out, alongside online comments about her body, where people described her as "chunky," 'tubby," "frumpy," and more.

Read more: Sydney Sweeney confirms split from Jonathan Davino

The actress shared in her W Magazine interview that she likes being active and being outside. She was on a ski team and has done wakeboarding, as well as playing soccer and softball.

She also trained in grappling from 13 to 19 and "fought all guys" at the dojo, where she was the only girl.

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