Taylor Swift Wrote 'All Too Well' About Ex Jake Gyllenhaal

Taylor Swift's secret's out!

The 22-year-old dated Jake Gyllenhaal two years ago, and on her latest album, Red, waxes philosophical about their relationship on the track "All Too Well," an insider confirms to Us Weekly.

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Calling Red her most "adventurous album yet," Swift told Good Morning America the writing process for "All Too Well" was a tedious one. "'All Too Well' was the hardest to write because it took me a long time to filter through everything I wanted to say," she admitted. "It started out being a 10-minute song, which you can't put on an album. I had to filter it down to a story that could work in the form of a song."

In the track, Swift reflects on her 2010 Thanksgiving outing with Gyllenhaal, 31, opening about spending the holiday at his sister Maggie Gyllenhaal's home in Brooklyn, N.Y.

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Swift even sings about a mysterious black and white striped scarf both she and Gyllenhaall wore during their courtship. "Left my scarf there at your sister's house / And you still got it in your drawer," Swift's lyrics read. While the ode is indeed about Gyllenhaal, a scarf thief he may not be. Consider: The knit in question could, in fact, be his! Both were snapped wearing the wrap, but he stepped out in it first on Nov. 11 and 15, long before Swift donned it for their Thanksgiving stroll in Brooklyn.

Writing songs about her failed romances has become a preferred pastime for Swift, who was dumped by Gyllenhaal around Christmas in 2010 -- via a phone call. "It's safe for her and it's something she loves," explains a source of Swift penning the tracks. "She goes back to it because it's something she's good at -- and she's not good at love."

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That's not to say Swift isn't still on the hunt for The One. Splitting from Conor Kennedy in October, the country queen is now "officially hanging out" with One Direction's Harry Styles, whom she recently bonded with at an X Factor taping. "Love is not a reality for her yet, but she knows it will happen," says the Swift source.

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