The 52-year-old frontman passed away on Wednesday (01.04.20) morning following a short battle with the respiratory illness, according to Variety.
Adam was reported this week to be “very sick and heavily sedated” by his attorney of 25 years, Josh Grier, who also confirmed the star was on a ventilator to help him breathe.
Josh said: "He's very sick and is heavily sedated, as are all people on ventilators, but no one has used the word 'coma' to me.”
The attorney also claimed the 'Crazy Ex-Girlfriend' songwriter has been receiving "excellent care" since his admittance last week but doctors were reluctant to make any predictions about his recovery because so little is known about the disease.
Following his hospitalisation, Adam's cousin Jon Bernthal took to social media to wish his relative a speedy recovery and asked his fans to keep him in their “heart”.
The 'Walking Dead' star wrote on Twitter: "This is my big cousin Adam. As a little boy I would be mesmerized by his talent. He showed me how cool it was to be an artist. We love you Cuz. Stay strong. Bless you and all of the hero's at the hospital on the front line. Please keep Adam in your heart. (sic)”
As of the time of writing, Adam’s family - including his wife Katherine Michel and their two daughters, Sadie and Claire - are yet to release a statement about his passing.
COVID-19 has claimed the lives of over 47,000 people since the outbreak began in Wuhan, China, late last year.
Over 934,000 people have tested positive around the world for the respiratory illness, which can cause a high temperature and continuous cough in those infected, as well as shortness of breath.
