'X Factor' duo Alex & Sierra got all Taylor Swift and Ed Sheeran (a la "Everything Has Changed') with their cover of One Direction's upbeat pop gem 'Best Song Ever.'

On tonight's (Nov. 20) episode, the duo turned the boys' hit into a dreamy, ethereal pop ballad with acoustic guitar. It was a total reworking of an anthemic track, and Alex & Sierra certainly took creative liberties with it. Directioners will either love it or hate it.

Speaking of 1D, the boys will take the stage for the American version of the TV show that produced them tomorrow (Nov. 21)!