Sydney Sweeney says she gained 30 pounds for Christy Martin biopic: “My boobs got bigger. And my butt got huge.”

"Echo Valley" European Premiere - Arrivals - Source: Getty
Sydney Sweeney attends the European premiere of "Echo Valley" at BFI Southbank in London, England, on June 10, 2025. (Image via Getty/Lia Toby)

Sydney Sweeney is getting candid about putting on weight for her forthcoming role as Christy Martin in the biopic and has revealed details regarding her preparation for the role.

The Euphoria actress, 27, spoke to W Magazine for its cover story about what it took for her to fully immerse herself in the role of the professional boxer for the upcoming biopic, which is being directed by David Michôd. Sweeney stated:

“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.”

Noting that her “body was completely different” as a result, and that she was 30 lbs heavier, Sydney Sweeney commented:

“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.” Nonetheless, she's a fan of her new looks: “It was amazing: I was so strong, like crazy strong,” she noted.

Here's everything we know about how Sydney Sweeney prepared for her role as heavyweight boxing champion Christy Martin

Sydney Sweeney's upcoming biopic is being helmed by Michod, who also penned the script alongside Mirrah Foulkes. It chronicles the tale of Martin's journey to becoming one of the most prolific female boxers in the ‘90s.

She made her debut in the field in 1989, and married her manager, Jim Martin, who was 25 years her senior. He was known for being abusive throughout their marital life, and in 2010, he stabbed and shot her. Today has reported that he was eventually sentenced to a 25-year stint behind bars, though E! News claims he died just last year.

Sydney Sweeney announced that she will be starring in the biopic on an Instagram post last year in October, which eventually went viral as fans were shocked at her physical transformation. She had captioned as following:

"Over the past few months, I've been immersed in training to bring to life the story of an incredible woman—a true champion who fought battles both inside and outside the ring"

Sweeney had added further:

"Her journey is a testament to resilience, strength, and hope, and I'm honored to step into her shoes to share her powerful story with you all."

Sydney Sweeney also uploaded a couple of photos of herself, dressed as the boxer, on set. In the most viral photo, she could be seen sporting a brunette wig and red sleeveless top as she flexed her bicep to show off her new gains. She told Deadline last year:

"christy's story isn't a light one, it's physically and emotionally demanding, there's a lot of weight to carry"

She continued:

"But I love challenging myself. Christy Martin not only legitimized female boxing, she overcame gender stereotypes and fought through emotional, physical and financial abuse."

Martin is the only woman in her field to have ever graced the cover of Sports Illustrated, in addition to being the first to sign with Don King, the famed promoter. She is also the first woman to join the ranks of others in the International Boxing Hall of Fame.

Martin, who also nabbed the World Boxing female super welterweight title in 2009, retired in 2012. She was famously known as "The Coal Miner’s Daughter” because of her father's job, though she is now largely credited with making women's boxing mainstream.

In her W Magazine interview, Sydney Sweeney revealed that she had seven weeks to shed the added weight for her next project - Euphoria Season 3. Although she didn't reveal how she did that, the actress did reflect on her love for 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,” she said. “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.”

On the other hand, Michôd, 52, told W Magazine:

“I hadn’t ever seen her in ‘Euphoria,’ I FaceTimed with her the other day when Sydney was in the makeup truck for the show, and I was stunned by the change in her appearance.” He added, “I had only seen her as an adorable, tough moppet with late-’80s hair, ready to box. Sydney was happiest when she was in the ring punching and being punched. It was shocking to see her being so glamorous.”

Sydney Sweeney and met her real-life counterpart just this New York for the Parade of Champions on June 8.

Edited by Ranjana Sarkar