"I was obsessed with *NSYNC," she tells Conan O'Brien. "Who wasn't?!"
But while millions of teenage fans fawned over Timberlake, Seyfried -- who would go on to costar with the now 31-year-old in "Alpha Dog" and "In Time" -- couldn't be bothered.
"[Justin] wasn't my favorite -- I didn't even find him attractive in fact!" she told O'Brien, instead pledging her allegiance to JC Chasez.
That's not to say that Seyfried doesn't think highly of Timberlake, who appeared as her love interest in In Time.
"He's a very respectful, intuitive man and in some ways, just the perfect guy for a woman," Seyfried has said of Timberlake, who proposed to girlfriend of four years Jessica Biel in December 2011. "He treats his mother really well. He's really funny. He has a lot of humility. He's just very aware."
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