The "Piano Man" singer announced on Friday, May 23, that he was canceling all of his concertsBilly Joel is "not ready to retire" following the news of his normal pressure hydrocephalus diagnosisSources tell PEOPLE that he is "happiest while performing" and that he hopes to return to the stageThe singer revealed on Friday,

Christie Brinkley is showing support for her ex-husband Billy Joel following news of his recent brain diagnosis. The supermodel, who shares daughter Alexa Ray with the legendary singer, posted a video on Instagram Saturday -- just one day after Joel revealed he had been diagnosed with normal pressure hydrocephalus.

Christie Brinkley and Billy Joel have been the friendly exes and that is on display after his recently shared medical diagnosis.