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"This Is Us" star Chrissy Metz is going to lose weight -- not just for her sake but also for the benefit of her character.

The actress appeared on "The Ellen DeGeneres Show" on Dec. 1 and spoke about her character on the hit NBC show. The host asked her if producers of the show told her to lose weight.

"Like most actors, we are chameleons," she said. "We play different roles -- like Christian Bale lost all that weight for 'The Machinist.'"

In a recent interview with TVLine, Chrissy said she was contractually obligated to lose weight. That, she considers, is a win-win.

"I was kind of like, 'I hope I get to lose weight.' That's a win-win for me -- motivated in a different way this time," she told Ellen. "It wasn't mandated. It wasn't like, 'You have to do this.' But if this is the storyline, naturally you would lose weight. So I'm excited if that should happen."

In "This is Us," Chrissy's character Kate considers going through gastric bypass surgery. Whether she'll do that in real life, she won't say.

"It is a fast fix, and it's not always the right answer," she said. "I can't give it away too much."

She added, "I think with the character, Kate, she wants a quick fix because it's not about the food. Food is the symptom. We'll get to see all the details."

While she told Ellen that her weight wasn't "mandated," she previously said that her contract mentioned she would have to shed some pounds.

"In our contract, it did state that that would be a part of it, to lose the weight in the trajectory of the character as she comes to find herself," she said in the TVLine chat. "I, as Chrissy, want to do things that mentally, emotionally and physically make me the best that I can be. That's the intention for our writers and the development of the character."