Atlanta: When Colonel Bruce Hampton slowly fell to his knees during the finale of his star-studded birthday concert, fans and musicians alike thought it was another one of his quirky performances.

Fourteen-year-old guitar phenomenon Brandon "Taz" Niederauer tore into a blistering solo as the 70-year-old man lay motionless at his feet, his arm draped over a speaker.

Bruce Hampton performs at the Fox Theatre. He died on stage as the concert neared its end. Credit:Getty Images

For several more minutes, dozens of musicians - including John Popper of Blues Traveler, Warren Haynes of The Allman Brothers Band and John Bell of Widespread Panic - jammed away to one of Hampton's favourite songs, Turn On Your Love Light.

The fans danced and the musicians smiled as they waited for him to get up.