You don't need a professional ear to realize that the uncredited background vocalist on Carly Simon's 1972 smash 'You're So Vain' belongs to Rolling Stones vocalist Mick Jagger.

When asked how the collaboration came out, Simon said, "He happened to call at the studio...  I said "We're doing some backup vocals on a song of mine, why don't you come down and sing with us?" (Guess these things aren't that complicated.)

Of course the biggest secret about this track isn't the guest singer, but who exactly the "vain" man is. Jagger's name has been bandied about for that honor, but so far all we know is that the mystery man does have an "e" in his name...

 

Hear 'You're So Vain' by Carly Simon