Who is that girl? Sydney Sweeney normally plays a blonde bombshell, but the 27-year-old looked unrecognizable as she transformed into boxer Christy Martin while filming a biopic about his life.

In photos obtained by The Post, the “Euphoria” star was seen wearing a short, curly brunette wig on Sunday while on the set of David Michôd’s new biopic in Charlotte, North Carolina.

Sweeney hid her famous hourglass curves in a full-zip, sweatshirt and t-shirt, while she channeled the WBC super welterweight champion’s iconic ’90s style with a blue bandana — her style years before her husband, James, tried to kill her.

Known as “The Coal Miner’s Daughter” because of her father’s job, Martin made her boxing debut in 1989 and is credited with bringing women’s boxing into the mainstream after taking on Deirdre Gogarty in front of cameras and a sold-out crowd at the MGM Grand in Vegas. Vegas in March 1996.

The fight landed her on the cover of Sports Illustrated in April 1996, making her the first female boxer to be featured on the cover of the swimsuit magazine. Her photo was accompanied by the headline: “The lady is a champion.”

However, her life took a turn in November 2010, when her manager-turned-husband, James, 66, stabbed her several times and shot her in the chest, leaving her for dead on the floor of her bedroom in Apopka, Florida. The then 42-year-old athlete survived the attack and James was arrested days later.

Her husband – who was almost 25 years her senior – was arrested in the Orange County Jail and charged with attempted first-degree murder and aggravated battery with a deadly weapon.

The couple married in 1991 and their marriage was fraught with problems, including drug use.

Martin — who later came out as gay and married Lisa Holewyne in 2017 — released her memoir “Fighting for Survival: My Journey through Boxing Fame, Abuse, Murder, and Resurrection” in 2022.

In May, it was announced that Michôd was directing a biopic about the boxer’s life and that Sweeney would play her. “The Righteous Gemstones” actor Tony Cavalero was cast in the role of James.

Martin was happy with the selection, telling TMZ: “I think she is young, beautiful and talented and is about to make a film that fathers will watch with their daughters in 20 years to raise awareness about domestic violence .”

“I want this film to raise awareness about domestic violence, the challenge of sexuality and the overall underdog story,” she explained. “I am the daughter of a coal miner from a small town in southern West Virginia who made a mark in a sport that was not taken seriously: women’s boxing.”

Sweeney said she was inspired by Martin’s story, and that she already had experience in the ring, having “wrestled and kickboxed from ages 12 to 19.”

“I was eager to get back in the ring, train and transform my body,” she told Deadline in May.

But that’s not why Sweeney took the role.

“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,” she said, adding that the boxer “overcame gender stereotypes and fought against emotional, physical and financial abuse.”

“I am passionate about the fighting world. Christy’s story shines a light on her incredible rise to the top while showing the battle for fame behind the curtains,” said Sweeney. ‘I feel compelled to tell a story about a woman who faced so much adversity and did not let it defeat her. It’s powerful and emotional.”