The American leg of the hugely successful Red Tour is over. But that didn't stop tourmates Taylor Swift and Ed Sheeran from reuniting for a quick reprise of sorts, to the delight of their fans.

Swift showed up and performed their powerful, acoustic, 'Red' album duet 'Everything Has Changed' with the British singer at one of his sold-out shows at Madison Square Garden in NYC.

The not-so-impromptu duet took place on Nov. 1.

Swift was met with deafening screams when Sheeran introduced her and thanked her for being such an integral part of his career.

The way Swift said "Hello, New York" when greeting the crowd sounded like the singer is very at home in the Big Apple.

Sheeran then invited fans to film with their cell phone cameras and to sing as loud as they wanted as he and Swift launched into a live rendition of the song with the guitars on which they wrote the track.

The adoring crowd obliged and the duo certainly had quite a choir of backup vocalists -- the crowd of thousands of rabid and impassioned fans, who screamed every word along with them.

It was quite a treat for fans of both artists.