Sydney Sweeney Gained More Than 30 Pounds for Christy Martin Biopic

Sydney Sweeney opened up in a new W Magazine cover story about her dramatic transformation into boxer Christy Martin for an upcoming biopic, saying that her “body was completely different” after months of intense training.

“I came onboard to play Christy, and I had about three and a half months of training,” Sweeney told the publication. “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.”

W also noted that the actor gained more than 30 pounds for the role.

“My body was completely different,” Sweeney said. “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.”

She added, “But it was amazing: I was so strong, like crazy strong.”

Sweeney is starring as Martin in an untitled sports biopic directed by David Michod, who co-wrote the script with Mirrah Foulkes. The film will chronicle the boxing star’s rise to become America’s most well-known female boxer of the 1990s.

Martin competed professionally from 1989 to 2012 and became the world champion in the super welterweight division in 2009. In 2010, she survived a murder attempt by her husband, James Martin, who stabbed her multiple times and shot her at their home in Florida. He was convicted of attempted second-degree murder in 2012 and sentenced to 25 years in prison.

In October 2024, Sweeney shared photos on Instagram of herself portraying Martin. “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,” she wrote. “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. more to come soon 🙂 CHRISTY MARTIN.”

The cast of the upcoming Christy Martin biopic includes Ben Foster as James Martin, Merritt Weaver, Katy O’Brien, Ethan Embry, Jess Gabor, Chad L. Coleman and Tony Cavalero. The movie is produced by Anonymous Content, Black Bear, Fifty-Fifty Films, Votiv and Yoki Inc.

Read Sweeney’s full W Magazine cover story here.