The 23-year-old country superstar sported a white top hat, tail-coat and hot pants as she belted out 'We Are Never Ever Getting Back Together'.
Halfway through the song she broke into a deep British accent to say: "So he calls me up and says I still love you.
"But I said, I'm sorry, I'm busy opening up the Grammys - and we're never, ever getting back together."
Taylor told 'American Idol' host Ryan Seacrest last week that she has no St Valentine's Day plans in the wake of her split with One Direction's Harry.
She joked she would probably be 'off in a warehouse somewhere' on February 14, 'working on the lighting rig and the lighting cues' for her upcoming tour.
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