Jam-band patriarch Col. Bruce Hampton died May 1 in Atlanta after collapsing onstage during a concert celebrating his 70th birthday.

The surrealist musician, known as the grandfather of the jam-band scene, was performing an encore of his Hampton 70: A Celebration of Col. Bruce Hampton birthday concert at the Fox Theatre when he died.

“After collapsing on stage surrounded by his friends, family, fans and the people he loved Col. Bruce Hampton has passed away. The family is asking for respect and privacy at this difficult time,” the family said in a statement posted on the Tedeschi Trucks Band’s Facebook page. The band was also part of the evening’s lineup.

The Fulton County Medical Examiner confirmed the guitarist’s death today.

After Hampton’s collapse, actor Billy Bob Thornton, who was also part of the lineup with members of Widespread Panic, Phish and other musicians, got on the microphone to thank fans and say they had to attend to something backstage.

Born Gustav Berglund III in Knoxville, Tenn., in 1947, the musician later adopted the stage name Col. Bruce Hampton, Ret., and co-founded the avant-garde Hampton Grease Band.

The band had one album — 1971’s “Music to Eat” — and earned a cult following before disbanding in 1973.

Hampton went solo after that, played a dwarf guitar called a chazoid (he once described it as “a perverted mandolin-cello” and said it was custom made) and also performed with the Late Bronze Age, the Aquarium Rescue Unit, the Fiji Mariners, the Quark Alliance and his latest collaboration, Col. Bruce Hampton and the Pharaoh Gummitt, according to his website.

Hampton’s band mate Jeff Mosier shared a tearful tribute on Tuesday morning on Facebook, recounting Hampton’s final moments.

“Tonight I witnessed the greatest gathering and concert and people I’ve ever been around. I’ve been lucky. I’m so lucky that I was there. … Only Bruce could have really brought together these people. … At the end, Bruce kind of looked like he was jokingly worshipping the young guitar player and he got down on his knees and, you know, I was getting ready to do the same thing. Just to be Zambi-like. … And Bruce didn’t get up and he later on died,” he said.

“I was lucky to know him and I was lucky to be there,” he continued. “And the last words he said were ‘get out there, Mosier,’ and we did. Everybody got out there. Music is my religion. The crowd was incredible and if you were in the crowd, consider yourself lucky. I will miss you so much, Bruce.”