Legendary singer-songwriter Billy Joel has made a triumphant return to the stage, surprising fans with his first live performance since being diagnosed with a debilitating brain disorder.

Concert-goers at a venue in Florida were expecting to see Billy Joel tribute act The Turnstiles, but instead got the real deal when the Piano Man himself walked out on stage.

“I wasn’t planning on working tonight,” Joel told the stunned crowd.

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Walking with a cane, the 76-year-old music legend was joined on stage by his two biggest fans – daughters Della and Remy.

Joel cancelled all his shows last May after being diagnosed with normal pressure hydrocephalus, a brain disorder that affects his walking and cognitive function. He has admitted to forgetting lyrics for years.

But performing We Didn’t Start The Fire, a song famously demanding on his memory, Joel didn’t miss a beat.

The emotional performance was met with thunderous applause, with Joel backing it up with his signature tune, Piano Man.

Hugs and handshakes followed for the star of the show, proving that it’s still rock and roll to him.

“Ladies and gentlemen, please give it up for my idol, Mr Billy Joel,” the tribute band’s frontman told the ecstatic crowd.