Possible Clues:

• Flamboyant pianist
• Pianist depicted in the biopic Behind The Candelabra
• Party time camaraderie unfulfilled showbiz entertainer
• Entertainer born in May 1919, the basis for five anagrams in this puzzle
• Be a relic (anag) - pianist
• Owner of the vanity plate '88 KEYS'
• Twentieth century American piano-playing entertainer
• Flamboyant twentieth century US pianist
• Late pianist with his own museum in Las Vegas, NV
• 11 from left getting one-two round back of defence