Taylor Swift Performs "You're So Vain" with Carly Simon

Carly Simon joined Taylor Swift on stage last night (July 27th) in Foxborough, MA to perform her hit-single, "You're So Vain."

A fan-shot video of the performance can be viewed below.

Don't forget, you can catch Taylor on tour this summer with Ed Sheeran. Remaining dates and ticket information can be found here.