“I couldn’t fit into any of my jeans anymore”

Sydney Sweeney is moving into new territory emotionally and physically with her role in the upcoming biopic “Christy” about US boxing legend Christy Martin.

For filming, Sweeney gained around 13 kilos of muscle mass in order to credibly embody the physical presence of the multiple world champion.

“I really had to gain weight, and I had to do it the hard way,” she told Sports Casting. “I ate so much that it was sometimes difficult for me. I drank one protein shake after another. My body completely changed. My breasts got bigger, my butt got huge. I couldn’t fit into any of my jeans anymore.”

Sydney Sweeney had to be very hard on herself

Preparing for “Christy” was not only a physical but also a mental feat for Sweeney. “It was really hard to gain so much weight during training,” she remembers. “I had to be very strict with myself. This wasn’t Hollywood bodybuilding, this was a physical challenge.”

But as soon as the last take was shot, the next race began: she only had seven weeks to regain the slim silhouette required for “Euphoria” and “The Housemaid”. “If you stop working out and drinking protein shakes, you lose muscle extremely quickly,” she explains. “Muscles disappear first, before fat. I completely lost them within two weeks.”

The rest, says Sweeney, came from “healthy eating and a lot of endurance training.” She never lost discipline. “I don’t want to say it was easy,” she emphasizes, “but I’ve been very active my whole life. I can gain weight and lose weight again. My body knows how to adapt.”

Between cinema and body consciousness

Sweeney is known for her uncompromising commitment to every role, whether as the fragile Cassie in Euphoria or the vulnerable outsider in Reality.

“The Housemaid”, a psychological thriller about an ex-convict who is drawn into a dark secret of a rich family, will be released in German cinemas on January 22, 2026. A German start date for “Christy” is still pending.

The 28-year-old has been in the headlines more often in recent months. In particular, American Eagle’s much-discussed fashion campaign (“Sydney Sweeney Has Great Jeans”) caused a bitter discussion that left its mark on the actress. She most recently dominated the tabloids with a sheer dress at an awards show (and Sharon Stone loved it!).