Is it Carly Simon looking into her past or maybe Taylor Swift into her future? Both ladies,while separated by generations, are superstars in music that are known for their songwriting ability.

Carly now joins a very long list of performers who have been a guest on stage at a Taylor Swift concert. She has sang with other 70's rock icons including James Taylor, and a slew of other rock, rap and country performers. I guess that is one one cool thing about going to one of Taylor's shows, you never know who may pop up.

SO if you missed it here is Taylor and Carly singing Carly huge hit, "You're So Vain" at Gillette Stadium.

What do you think?