Gurl has done it again!
Swifty had Rascal Flatts pop onto stage with her in Nashville to perform What Hurts the Most!
And the duet is just as AH-Mazing as expected!
What's super sweet about their appearance is she once toured and opened for them before she was a big, mega, huge superstar!
Ch-ch-check out the incredible duet…AFTER THE JUMP!!