Southern rock icon Gregg Allman died at age 69 on Saturday, leaving the music world devastated.

“It is with deep sadness we announce that Gregg Allman, a founding member of The Allman Brothers Band, passed away peacefully at his home,” the band’s official Twitter account tweeted after Michael Lehman, Allman’s longtime friend and manager, announced the tragic news.

Allman’s ex-wife Cher was one of the first to voice her sorrow on social media, lovingly referring to him as “Gui Gui.”

Ringo Starr and Allman’s fellow Southern rock musician, Charlie Daniels of the Charlie Daniels Band, expressed their grief as well.

Fellow musician Bob Seger said Allman was “one of my favorite rock singers of all time” in his tribute, adding how he put “immense soul into his music.” He concluded: “So sad, we’ve lost another music titan.”

British rocker Peter Frampton described him as “a gentle soul with so much soul.”

Sheryl Crow posted a photo from a performance with Allman to Twitter. “Broken heart. Gregg Allman I will miss you,” she wrote.

It is currently unknown what caused the singer’s death. As recently as April 24, reports surfaced claiming Allman was in hospice. However, his manager denied those reports, which Allman then substantiated in a Facebook post.