well, BB used to sing every sunday in a choir at church, and he has played the guitar for them after a while. It's not really 'lessons' but I guess you can consider that he has been taught by everyone in this choir.
Last time, I have played with a full organ for a wedding, and dude, that taught me a lesson in 'spectrum placement' cause if you play with a rock band and nobody can hear you, you can turn it up or play harder... That doesn't work with a church organ (cause it's so loud. You have to find the spot that the organ isn't filling...
After a while, we have played an improvised Fugue, that was so cool... Every musical experience is a lesson, to me...