Well this is certainly a strange date night!
How do we know?
You'd think they wanted to dance to the music together!
Ch-ch-check out their videos (below)!!!!
Most of Taylor Swift's fans are probably too young to have been around when Carly Simon was blazing up the charts.
Well, except for that 39-year-old guy that won the biggest fan contest…
But for a music aficionado like Taylor, doing a duet of You're So Vain with the legendary singer must have been like a dream of clouds in her coffee.
We're not sure what that means, but Taylor totally got to do it Saturday night at her concert in Foxboro, MA!
Carly walked onstage like she was walking onto a yacht. But it was Taylor that reeled! Even knowing the surprise was coming, gurl was still visibly nervous to perform with her hero!
See the duo sing a song that John Mayer probably thinks is about him …AFTER THE JUMP!!!
[Image via Facebook.]