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

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.

Billy Joel has the support of his family, including his ex Christie Brinkley and their daughter, Alexa, amid his diagnosis with a rare type of dementia.