Sydney Sweeney is ready to enter the ring.

The actress shared some behind-the-scenes footage (below) from her time on the set of the Christy Martin biopic in which she stars.

“Well the cats are out of the bag thanks to some paps in the bushes so here are some bts from my movie I’m working on right now,” she wrote in an Instagram caption alongside two photos of her in sweats with a brown, curly haircut. “Over the past few months, I have immersed myself 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 concluded: “Her journey is a testament to resilience, strength and hope, and I am honored to walk in her shoes and share her powerful story with all of you. More soon.”

David Michôd will direct the currently untitled film that follows the true story of Martin’s rise to become one of the most famous female boxers in 1990s America. Ben Foster, Merritt Wever, Ethan Embry and Katy O’Brian also star in the biopic.

Martin began her career in 1989 after meeting manager and eventual husband Jim Martin. She continued to compete until 2012 and is the only female boxer to appear on the cover to date Sports illustrated.

But the athlete’s life has not been without struggle. In 2010, her husband stabbed her repeatedly and shot her in the chest, leaving her for dead. She managed to find the strength to run out of the house and flag down a passerby, who took her to the hospital. Two years later, Jim Martin was sentenced to 25 years in prison for attempted manslaughter with a firearm.

The boxer told CBS News that his abuse of her took many forms, including sexual and emotional. She explained that he got her addicted to cocaine and gave her a steady supply. He also blackmailed her and threatened to reveal her sexual orientation.

“The whole sexuality part is really hard because I was so intertwined,” she told the station. “First of all, I trusted Jim Martin, and he was 25 years older than me. He was my coach. I felt like this was someone I could open up to and bear my soul, and tell him all about my sexual struggles, my struggles with my family, just the struggles in life, and all of that was used against me .