Sydney Sweeney gets into character with a new look as she prepares to play a boxer Christi Martin in an upcoming biopic.

“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,” Sweeney, 27, wrote via Instagram on Wednesday, October 16, alongside some first photos of her on the set. “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.”

In the photos, Sweeney showed how she traded in her iconic blonde locks for a curly brunette hairstyle with bangs. The actress wore gray sweatpants, a red cut-off T-shirt and white sneakers.

Sweeney also proved that her training paid off. In one fell swoop, she flexed her super-strong arm muscle and smiled happily as she celebrated her new jacked physique.

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“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,” the actress continued. “More soon :).”

The project was first announced in May and Sweeney shared how excited she was to get started.

“I wrestled and did kickboxing from 12 to 19 years old. I was eager to get back in the ring, train and transform my body,” Sweeney said in an interview with Term at the time. “Christy’s story is not light, it is physically and emotionally demanding, there is a lot of weight to carry. But I like to challenge myself.”

Although the film is not yet titled, it is being directed by David Michod. In addition to Sweeney, the cast also includes Ben Foster, Merritt Weaver, Ethan Embry And Katy O’Brian.

The film follows the life of Martin, now 56, and her journey to becoming one of America’s most successful female boxers. Martin started her career in 1989 after meeting her manager and later husband James Martin. She went on to win the World Boxing female super welterweight title in 2009. She continued boxing until 2012.

In 2010, Christy almost died after being attacked by James. He was arrested and charged with attempted first-degree murder and aggravated battery with a deadly weapon. Two years later, James was found guilty of attempted manslaughter. He is currently serving a 25-year prison sentence.

Christy was the first female boxer elected to the Nevada Boxing Hall of Fame in 2016. She was also elected to the International Boxing Hall of Fame in 2020, the first year women were included on the ballot.