As has become customary over the last month, Swift previewed the song on Monday's edition of "Good Morning America." In an interview, the pop star explained that the new tune is about "kind of being frustrated with yourself because you have your heart broken and you knew when you first saw that person you saw all these red flags and you just went for it anyway." In classic Swift style, she spins the sob story of a failed relationship into an upbeat country-pop song.
Swift started her appearances on "GMA" at the end of September, debuting "Begin Again," and the album's title track, "Red," the following week. Oct. 15 will mark her final song tease before the album's official launch on Oct. 22.
"I Knew You Were Trouble" is available for download. Listen above.