One Tree Hill, Lee Norris

When One Tree Hill returns on Wednesday (8/7c, CW) one character will be virtually unrecognizable.

"Mouth [has] gained about 60 pounds," Lee Norris tells TVGuide.com. "He's undergone a physical transformation ... but what is really going to interest the audience is why this transformation happened."

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When we last saw Marvin "Mouth" McFadden, he and girlfriend Millie (Lisa Goldstein) had begun their very own morning show. While the two are still at it when the show returns, they'll have a lot on their plate.

Castmate Rob Buckley has hinted that one of the major characters would die. Is Mouth's weight gain a symptom of a life-threatening illness? Is it due to emotional issues? "I was so adamant about handling this topic with respect because I know so many people that struggle with it," he says. "I didn't want it to be one of the broader comedic things on the show; I wanted it to be an issue that people identify with."

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Norris said that he didn't actually gain the weight, but that he spent four hours in makeup every morning to complete the look. "It was an amazing opportunity to tackle something [he] never thought I'd never get to do," he says.

Check back for more on One Tree Hill's final season.