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Amanda Seyfried fully supports her Dear John co-star's title as People's 2012 Sexiest Man Alive, telling InStyle magazine that he's a "superstar."

"Channing was amazing," the actress, 27, recalled of working with the heartthrob (via The Huffington Post). "Everybody wants to have sex with him. And the only person he wants to have sex with is his wife, Jenna [Dewan-Tatum]. He's the most loyal husband."

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As for Seyfried's love life, she's admits she hasn't been quite so lucky. "The thing is, I can't date anybody without it being portrayed as a serious relationship in the tabloids. It sucks!" she told the magazine. "Like Josh Hartnett and I were friends; we hung out, we dated. I don't actually have sex with every male I come into contact with."

While Seyfried is already gaining lots of attention for her Oscar buzz-worthy film Les Miserables, out Christmas day, the actress is also set to star as porn star Linda Lovelace next year, a role that is sure to include nude scenes. "It's not about my body. It's not about me. You're playing somebody else. You're not going to believe a love scene if the people are dressed. You're not going to believe a stripper who has on a bra and underwear the whole time."

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Seyfried adds, "At the same time, it has to do with how comfortable you are with letting people see your skin. For me, I'm okay with it."