Holy headbang! Taylor Swift left her heart on the floor while performing at the 2014 Grammy Awards in L.A. Sunday night. The songstress sang a stripped-down piano performance of "All Too Well," believed to be about ex Jake Gyllenhaal.

Swift, 24, let her blonde locks down as she gave a powerful and intimate piano performance of the song off her nominated 2012 album Red. "'Cause there we are again on that little town street," she belted. "You almost ran the red 'cause you were looking over me/ Wind in my hair, I was there, I remember it all too well." Half-way through the set, the star stepped it up a notch as she violently threw her head back not once, not twice, but seven times(!) while simultaneously keeping time with the emotional ballad.

Two days earlier, the "I Knew You Were Trouble" singer teased her fans about her upcoming performance. "Today at rehearsals for grammys. I'm trying to remember.. What was the song a lot of you were saying…" she tweeted on Jan. 24. 

Us Weekly exclusively broke news that Swift and Gyllenhaal, 33, ended their very public, yet brief romance in January 2011 after two months of dating. "Jake just told her it wasn't working out...Taylor is really upset and hurt," an insider explained to Us at the time of Gyllenhaal pulling the plug. "She doesn't know what she did for him to put a stop to it. She feels really burned by him."

Us confirmed in November 2012 that the song was ultimately penned about the Nightcrawler actor, but there doesn't seem to be bad blood between the two exes. After all, writing about her exes is what she's known for. "It's safe for her and it's something she loves," an insider told Us of her writing ways. "She goes back to it because it's something she's good at -- and she's not good at love."

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