Sydney Sweeney discussed her physical transformation for the biographical sports drama Christy during a panel at the Toronto International Film Festival, a day after she became emotional at the film’s premiere while praising the real-life boxer she portrays.

At the Variety Studio discussion on Saturday, Sweeney described the regimen she followed to inhabit the role, saying she worked with a nutritionist, a weight trainer and a boxing coach and that the production required a sustained increase in calories. "We upped my calorie intake and I started taking a lot of protein shakes and supplements and eating everything," Sweeney said, adding that she consumed "a lot of Smuckers, a lot of PB and J sandwiches, milkshakes" to bulk up and sustain intense training. She said the team trained multiple times daily during preparation and while filming, calling it "quite a challenge." (Quotes to Variety.)

Sweeney, 27, who portrayed former welterweight champion Christy Martin in the film directed by David Michôd, attended the panel alongside cast members including Ben Foster, Merritt Weaver, Katy O'Brian, Ethan Embry, Chad L. Coleman and Tony Cavalero. Christy is scheduled for theatrical release Nov. 7.

The day before the panel, Sweeney wept openly at the film’s TIFF screening while addressing Martin. Wearing an Erdem blush corset gown, she told the former boxer, "Christy, you are absolutely incredible, and I'm so honored. I'm gonna cry! Oh my God, you're so inspirational," according to Variety. Martin, who attended the screening and has praised Sweeney’s portrayal, said the actress became "the tough, rugged Christy," rather than playing a glamorous version of herself.

Sweeney’s appearance at the panel drew attention beyond her comments about training. At the Variety event she wore a gray cropped blazer with a deep neckline and matching trousers featuring sheer corset detailing. Her look, accompanied by understated jewelry and waved hair, was photographed at the festival.

The TIFF events come amid a period of heightened public scrutiny for Sweeney. In late July, American Eagle launched an ad campaign featuring the actress with the tagline that drew criticism from some commentators who said the slogan recalled discredited eugenics rhetoric. The campaign prompted debate on social media and in entertainment coverage.

Separately, media reports have linked Sweeney romantically to music executive Scooter Braun; People reported the two spent Labor Day weekend together at Lake Tahoe. Sweeney split from her fiancé, Jonathan Davino, in March.

Christy represents a significant role for Sweeney, who has faced mixed box-office returns for recent films. Her most recent features, Americana and Eden, did not perform strongly at the box office amid tepid reviews, industry observers said; the response to Christy at TIFF will be watched as the film heads toward its November release.

Michôd’s film aims to dramatize Martin’s rise in professional boxing and the challenges she faced inside and outside the ring. Sweeney said portraying Martin required both physical and emotional commitment, and she described the experience as "incredible" and "truly inspiring" as she worked to inhabit the athlete’s strength and presence on screen.