For the better part of nearly 40 years, he's been the right-hand man of one of the biggest stars in rock history. Can you guess who he is from this yearbook photo?

When not playing guitar and singing backup with his friend, he still keeps plenty busy as an actor, radio host, record label owner and, most recently, film and theatre producer. In his solo career during the '80s, his songs often reflected his political activism, and had a hit in 1987 by bringing together some of the day's biggest names in rock, jazz, pop and rap. Still, it may be hard to recognize him without his trademark babushka on his head, so if you're still unsure of his identity, click below to find out!