Sydney Sweeney must be used to fans commenting on her appearance by now after her latest dramatic transformation.The Euphoria actress looks unrecognisable as female boxing icon Christy Martin after playing the pioneer in an upcoming biopic.Sweeney is playing the trailblazing boxer Martin, who was nicknamed ‘female Rocky’GettyBut before the 27-year-old was sparking controversy for her ‘great jeans’, she was struggling to fit into them after lacing up the gloves.Sweeney first teased her transformation into Martin with two behind-the-scenes photos that she shared in October.The Hollywood star has now swapped her long blonde locks for the boxer’s curly brown hair in the first official snaps shared this month.‘Christy’, which will debut at the Toronto Film Festival in September, showed Sweeney in a white tank top, tasselled shorts, a mouthguard, and red boxing gloves for the first official still from the film.“I came onboard to play Christy, and I had about three and a half months of training,” Sweeney told Variety last month.“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.”Speaking to W Magazine, Sweeney revealed that her vigorous workout regimen for the role led her to gain 30 lbs (13.7 kg).“My body was completely different,” she added. “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.” But it was amazing: I was so strong, like crazy strong.”The actress has shared the first official photo of herself as Christy Martin@sydney_sweeneySweeney underwent a dramatic body transformation after extensive trainingAFPWhy is Sydney Sweeney playing Christy Martin?Sweeney, who is a big fan of Ronda Rousey and has prior combat experience, has claimed she has been compelled to tell Martin’s story.“I grappled and did kickboxing from 12 to 19 years old,” Sweeney told Deadline last year.“I’ve been itching to get back into the ring, train, and transform my body.“Christy’s story isn’t a light one; it’s physically and emotionally demanding, there’s a lot of weight to carry. But I love challenging myself.”She added: “Christy Martin not only legitimised female boxing, she overcame gender stereotypes, and fought through emotional, physical, and financial abuse.“I’m passionate about the fighting world. Christy’s story shines a light on her incredible rise to the top while showing the struggles of fame behind the curtains.“I feel compelled to tell a story about a woman who faced so much adversity and didn’t allow it to defeat her. It’s powerful, and emotional.”Sweeney’s latest role has transformed her from Hollywood glam to boxing pioneerGettySweeney showed her transformation to her millions of followers on Instagram@sydney_sweeneyWho is Christy Martin?Before Katie Taylor and Amanda Serrano, Christy Salters Martin was paving the way for female fighters.She became a world champion and was the first female boxer to appear on the cover of Sports Illustrated.Martin even stole the spotlight away from a prime Mike Tyson on his undercard in 1996 against Deidre Gogarty.The 57-year-old gripped fans in a fight which Sports Illustrated said had ‘more action and better boxing’ than Iron Mike’s fight with Frank Bruno.However, sadly, her personal life was filled with tragedy and trauma.Martin’s life was transformed in 1989 when she met her manager and soon-to-be husband, Jim Martin.The toxicity of their relationship was highly publicised, and things took a dramatic turn when Christy was stabbed multiple times and shot by her ex-husband at their house in Florida in 2010.In June 2012, Jim was found guilty of attempted second-degree murder and sentenced to 25 years behind bars.Martin compiled a 49-7-3 record and 31 knockouts throughout her careerGettyShe later remarried former ring rival Lisa Holewyne in 2017.The pair fought in 2001 on the undercard of Lennox Lewis vs Hasim Rahman 2 at the Mandalay Bay in Las Vegas.“She boxed circles around me,” Holewyne told ESPN. “It was aggravating.“At the weigh-in, when I got off the scale, I said, ‘Good luck, Martin,’ and she said, ‘Good luck getting knocked the f*** out.’“Those were our first words to each other.”Martin now promotes fighters as the CEO of Christy Martin Promotions, after retiring in 2012.