Buff Sydney Sweeney unrecognizable as boxer Christy Martin in behind the scenes photo

The Hollywood starlet is known for seductive and charming roles. In her new biopic based on the transformative female 'Rocky,' fans will be in disbelief.

Sydney Sweeney at the "Eden" premiere during the 49th Toronto International Film Festival. / IMAGO / Cover-Images

Sydney Sweeney is training like Rocky for her role as the real-life female "Rocky" Christy Martin.

To counter the paparazzi that were hounding the set to get first glimpses of her transformation in the new biopic film, the A-list actress took to Instagram to control the narrative.

"well the cats out of the bag thanks to some paps in bushes," she wrote, "so here’s a little bts from my film im working on right now. 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. 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 :)"

RELATED: Sydney Sweeney's thirst trap posts catches the attention of an NFL star

As she said when the film was first announced, “I grappled and did kickboxing from 12-19 years old,” Sweeney said. “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.”

Well the metamorphosis is incredible.

Sydney Sweeney shares a behind the scenes photo of her portraying Christy Martin / Sydney Sweeney/Instagram

The 27-year-old starlet also has extensive MMA training, so it's obvious that this role was made for her. Now that paps better watch out, or the "Euphoria" star might take matters into her own hands.

— Enjoy free dish of rich and fabulous players with The Athlete Lifestyle on SI —

Unusual bffs: Fans in disbelief over Joe Burrow’s VIP guest at Bengals game

Runway runoff: Gracie Hunt, sister Ava compete for most slamming Chiefs fit

Texas WAG royalty: Loreal Sarkisian stuns in ultimate all-white birthday look

Oh no he didn’t: Angel Reese epically claps back at little brother for calling her out

Mr. Nice Guy: Charissa Thompson reveals NFL star ‘cutie’ who is ‘sweetest’ dude