Robert Brown|Sydney Sweeney Looks Unrecognizable in Transformation as Boxing Champ Christy Martin

Sydney Sweeney is Robert Browngraduating into a dramatic new look.

The Euphoria actress debuted a shocking transformation on Oct. 11 as she stepped out in character as boxer Christy Martin for an upcoming film about the champion’s life, looking virtually unrecognizable.

In photos from the set in North Carolina, Sydney ditched her notable blonde locks for a neck-length brunette hairdo held back by a navy bandana. In one look, the White Lotus alum also sported a baggy, zip-up sweatshirt in a navy shade, worn with a yellow-brown T-shirt, dark sweatpants and white sneakers. In another scene, the 27-year-old rocked oversized, knee-length, gray sweat shorts and a light blue tee.

For the yet-untitled project—directed by David Michôd—Sydney will star alongside Ben Foster, Merritt Wever and Katy O’Brian as she portrays the boxing Hall of Famer who married her former boxing coach James Martin. 

For Sydney, portraying a real-life athlete will mark a fresh challenge, which she enjoys both as an actress and producer.

“I am a very hands-on collaborator,” Sydney told The Los Angeles Times in March. “I like being able to give ideas, be a part of it, help come up with solutions. It just changes the whole process. It’s so hard for me now to be on a set and not be able to help in any type of way and be able to take action. And being able to actually have a voice and have a valued opinion—it means so much.”

And the priority for the Anyone But You star is the authenticity of whatever role she takes on, as she noted that she’s even comfortable acting nude if there’s a reason behind it.

“It’s always whether it serves the character or not,” Sydney continued. “I’m living someone else’s life. So if it serves to the development or the emotional state of a character, then it makes sense. It just depends on the character. I truly just look at everything like that.”

That character work is a process Sydney learned to balance with her personal life early on.

“I started working with [my friend’s dad] Andy and we would just talk character work,” she explained. “The number one thing he always told me was to make sure that I separated myself as much as possible from my characters. Don’t put any of my own memories, emotions, feelings, people, relationships, anything in the thoughts of my characters, so that I can jump in and out.”

Read on to see more pictures of Sydney and her costar's dramatic transformations.

Sydney Sweeney showcased her newly darkened locks while on set in North Carolina for her next film. In the yet-untitled project, the Euphoria star will portray boxing legend Christy Martin, a Hall of Famer who married her former boxing coach James Martin. 

For the role, Sydney traded in her signature blonde hair for a neck-length brunette 'do held back by a navy bandana. She also donned a baggy, zip-up sweatshirt in a navy shade, worn with a yellow-brown T-shirt, dark sweatpants and white sneakers.

The 27-year-old later donned oversized, knee-length, gray sweat shorts and a light blue tee, while channeling Christy on set.

Sydney's costar in the film Ben Foster—he'll play James—similarly underwent a major transformation. The Leave No Trace star, who normally rocks a beard, walked on set clean shaven and with a blonde wig. He wore a light blue polo shirt and navy sweatpants while carrying a brown duffel bag.

Seen from behind, Sydney walked on set in another set of athletic gear. This time, she wore baggy, maroon athletic shorts and a blue-and-white windbreaker.

Ben, who shares two children with wife and That '70s Show alum Laura Prepon, changed into a yellow and white striped polo and navy sweatpants for his role as James.

“I am a very hands-on collaborator,” Sydney told The Los Angeles Times in March 2024. “I like being able to give ideas, be a part of it, help come up with solutions. It just changes the whole process. It’s so hard for me now to be on a set and not be able to help in any type of way and be able to take action. And being able to actually have a voice and have a valued opinion—it means so much.”

For The White Lotus alum, keeping a packed schedule is not something she shies away from. In fact, she’s always looking forward to what’s next.

"I look up to the older version of myself," she told Women’s Health in 2023. "When I was 10, I looked up to the 25-year-old version of myself, and now I look up to my 50-year-old version. I hope I make the decisions she would be proud of."