"My December:" Taylor Swift Says Sorry in New Song

Taylor Swift performs at the MTV Video Music Awards on Sunday, Sept. 12, 2010, in Los Angeles.
AP Photo/Matt Sayles
Taylor Swift arrives at the premiere of "Easy A" on Sept. 13, 2010, in Los Angeles.
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NEW YORK (CBS) Taylor Swift is saying sorry in her new song "My December," which was released on iTunes Tuesday - but she won't say whom the apology is for.

The 20-year-old singer said the tune is the first time she's ever apologized in one of her songs.

Pictures: Taylor Swift

"It's the first time I've ever admitted guilt in my music," she told USA Today.

In the song, Swift laments how she ended a romantic relationship. She explained in the interview that she based the song on a conversation she had with the guy about whom she's singing.

"It's not loosely based," she revealed. "It's almost word-for-word. It is a song and a conversation that needed to happen, because I don't want to hurt people. If you unintentionally do so, you've got to make that better."

But who is the mystery man? Could it be "Twilight" star Taylor Lautner, whom Swift briefly dated last year? She wouldn't say.

"I feel so comfortable singing about these details and these relationships and listing times, dates, details, names," she said. "But when it comes to an interview and they say, 'Are you dating this person?' or 'Did you date this person?' or 'What's your current relationship status?' I suddenly feel very shy."

"It's such an interesting little quirk. It's like, 'Obviously, you're writing songs about your life and you're almost admitting to these things.' But when it actually comes time to talk about them in an interview, I get pretty shy and coy about it," she continued.

"Back to December" is from Swift's upcoming album "Speak Now," the follow-up to her 2008 album "Fearless."