This Taylor Swift And Demi Lovato Mashup Is Heaven For Your Ears

    Demi Lovato's "Heart Attack" and Taylor Swift's "I Knew You Were Trouble" have never sounded so amazing.

    Rachel Horner
    by Rachel Horner

    BuzzFeed Staff

    Prepare to have this on repeat for at least a week.

    Demi Lovato: Frederick M. Brown / Getty Images / Taylor Swift: Ethan Miller / Getty Images
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