Casey Kasem is considered the voice of America by most people.

Not only was he the voice of Shaggy on the Scooby Doo show, he was also a DJ and hosted some of the most popular music radio programs, including American Top 40, American Top 20, and American Top 10 from 1970 until his retirement in 2009.

Kasem passed away on Sunday, June 15 from complications of his dementia. He was 82 years old.

He is survived by his wife, children and grandchildren.

His death was mourned around the world, but many of his celebrity friends who knew him well also mourned the loss of their friend on Twitter.

Keep your feet on the ground and keep reaching for the stars. We’ll miss you, Casey. pic.twitter.com/cxYhONfrqz

— Ryan Seacrest (@RyanSeacrest) June 15, 2014

Long before MTV and the internet #CaseyKasem made sure you were hearing the best music out there. Peace be to his family and RIP. #Respect

— Carson Daly (@CarsonDaly) June 15, 2014

We've lost a music industry icon. Chngd the industry w/AT40 Cntdwn. RIP Casey Kasem. "Keep ur feet on the grnd & keep reaching 4s"

— Marie Osmond (@marieosmond) June 15, 2014

RIP Casey Kasem. My thoughts are with his children who didn't get time with their father before his passing. So sad.

— oliviamunn (@oliviamunn) June 15, 2014

RIP Casey Kasem who inspired all of us in radio & turned millions of people onto music.Sending love to @KerriKasem, family and friends.

— Nikki Sixx (@NikkiSixx) June 15, 2014

RIP Casey Kasem…I'll never forget what a joy it was to hear him say, "From Newport Beach, CA….here's Sugar Ray!"

— mark mcgrath (@mark_mcgrath) June 15, 2014

Kasem was diagnosed with Parkinson’s disease in October 2013. The diagnosis was later changed to Lewy body dementia. His family tried to keep the illness a secret, but on June 6, 2014, Kasem was reported to be in critical but stable condition at a hospital in Washington state.

His condition continued to deteriorate and he passed away at the hospital on June 15.

His body was turned over to his wife, who is currently making funeral arrangements.

Image via Wikimedia Commons