The Sydney Sweeney boxing biopic isn’t just another “actor gets in shape for a role” headline. Sweeney went all in. She gained 35 pounds, built muscle, trained in real boxing gyms, and stepped into the life of Christy Martin, the woman who helped bring women’s boxing into the mainstream in the ‘90s. And while that story alone is headline-worthy, it comes at the same time Sweeney found herself pulled into unexpected Hollywood controversy involving Kim Novak. This means her latest career turn is as political as physical.
The Making of a Fighter
For the upcoming film Christy, Sydney Sweeney learned to throw a punch, but she also gained roughly 35 pounds, telling People her “body looked and felt completely different.” She trained with professional fighters to get her stance, footwork, and strength right. According to EW, she lifted weights, sparred, and spent months doing intense conditioning, even as filming approached. She went up two clothing sizes and embraced it, not because she was chasing a transformation moment, but because she wanted to honor what Christy Martin looked like in the ring.
Martin wasn’t a lightweight. She was a knockout machine with a record 49 wins, 31 by KO, and her fights were so popular that she wound up on the same card as Mike Tyson. That’s the legacy Sweeney’s stepping into.
The Sydney Sweeney boxing biopic explores the darker side of Martin’s life, including the abusive relationship with her trainer-husband, Jim Martin, who was eventually convicted of trying to kill her. It’s a story about survival, self-definition, and fighting in and out of the ring. Ben Foster plays Jim, which means the film likely won’t sand down the sharp edges of what happened.
Christy Martin, now 56 and working in sports promotion, visited the set and supported Sweeney’s performance. In multiple interviews, Martin said that Sweeney “got it,” and the two connected instantly over the emotional weight of the role.
Not Just Boxing: The Kim Novak Complication
While the gloves were going on for Christy, Sweeney was also caught up in another project: a biographical drama about actress Kim Novak and her romance with Sammy Davis Jr. The film, still in development, made headlines when Novak herself expressed concern that the script might turn her life into sensationalism rather than a portrait of its real cultural stakes. Novak said she hoped Sweeney would treat the story “with respect instead of sexual shock value,” which naturally put pressure on Sweeney and the filmmakers.
What’s interesting is how these two projects collided at the same time. One about a woman who fought her way into a male-dominated sport, the other about a woman who faces racism, censorship, and Hollywood control. Both ask questions about who gets to tell a woman’s life story. And both put Sweeney in the position of not just performing, but interpreting.
Sweeney hasn’t publicly addressed the Novak comments, but sources close to the project say the film is still moving forward. Sweeney has been involved in script review and historical research; signs she’s not approaching it lightly.
What to Expect from the Sydney Sweeney Boxing Biopic
Christy is set for release in November 2025, and the studio is keeping most spoiler-heavy plot details under wraps. What’s clear, based on Sweeney’s training timeline and Christy Martin’s own comments, is this: the film will not be a glossy, motivational biopic. It’s going to deal with violence, fame, and the politics of women in sports, and how Martin rebuilt her life after nearly losing it.
Sweeney’s fans have gotten used to seeing her in anxiety-coded roles on Euphoria, Reality, and Anyone But You. Christy, the Sydney Sweeney boxing biopic, is something new, a physical and bruising personal performance.