"In the 1960's we would meet at one of the late-night music clubs and often go back to his house where he had a huge and glorious collection of records," McCartney writes on Instagram. "During these moments he became a mentor and would educate me on a lot of the blues guitarists playing at the time."
Mayall's band Bluesbreakers was a breeding ground for future well-known rock stars. Different incarnations of the band featured such artists as Clapton, Fleetwood Mac's John McVie, Mick Fleetwood and Peter Green, The Rolling Stones' Mick Taylor and Cream's Jack Bruce.
Mayall is due to be inducted into the Rock & Roll Hall of Fame in October in the Music Influence category.