Steve Winwood

Steven Lawrence Winwood is most famous for his solo work, including two number one hits Higher Love and Roll with It, and for being the member of two supergroups, Traffic and Blind Faith, along with helping found the Spencer Davis Group at fourteen years old.

Speaking of which, Mozart had nothing on Winwood as a keyboard virtuoso:

As a boy in middle school, little Stevie Winwood played the Hammond synth for Blues gods and Rock & Roll founders like Muddy Waters, John Lee Hooker, Howlin' Wolf, B.B. King, Chuck Berry and Bo Diddley, when they toured in Britain. We’d list more, but it’s exhausting to link all of those names.

https://www.youtube.com/watch?v=VwqsmNR_Q1M
Stevie Winwood playing keyboard at 15 years old.