For those of you who haven't watched Frozen over, and over, and over, AND OVER, again - either by choice or under duress - that's Olaf. Or rather, that's Taylor's rather inspired Olaf costume. She marked the final US show from her 1989 tour by inviting Idina Menzel onstage (dressed as Elsa, natch) to bang out one of the world's most warbled songs. And it was pretty special. 

Clearly moved by the inspired move, Swift posted the below to Instagram, captioned: "Frozen totally happened tonight. And 55,000 people sang 'Let it Go' so loudly, it nearly took my breath away. Good times, @idinamenzel."

Prior to bringing Idina onstage, Taylor banged out a couple of her hits dressed as Olaf, which is to be commended given it must've been hotter than the fires of hell in there. 


As for Idina herself, she obviously had the time of her life.