Billy Joel is convinced he's the session musician playing piano on THE SHANGRI-LAS classic LEADER OF THE PACK - but he never got paid.

The PIANO MAN, 56, recorded the 1964 track before the girl group added their vocals and he's certain he's the man tinkling the ivories on the hit, despite being only 15 at the time.

He tells music magazine Rolling Stone, "I'm pretty sure it was me. I saw an interview with ELLIE GREENWICH (song's co-writer) and she said it wasn't me.

"I never got paid, though, so it doesn't make any difference."