"You and I both know / This river will surely flow to an end / Keep me in your heart / Keep your soul on the mend," Allman sings on the six-minute Southern rock ballad.
"I hope you're haunted by the music of my soul / When I'm gone, please don't fly away / And find you a new love / I can't face living this life alone / I can't bear to think that this might be the end."
The video pairs the song's lyrics with scenic images of Allman's beloved Georgia and footage of the rocker in the studio with his band.
While the track might seem like Allman's acknowledgement of his own mortality – especially in the face of his medical issues during recording – "My Only True Friend" is actually written from the perspective of Gregg's late brother Duane Allman, as co-writer Scott Sharrad told Rolling Stone.
"I never told him because I didn't want to spook him, since his brother was such an important figure in his life," Sharrad said, adding that the song was written in the voice of Duane talking to Gregg.
Southern Blood producer Don Was said of the upcoming posthumous LP, "It's not an album about dying. Gregg was explaining his life and making sense of it, both for the fans who stood with him for decades, and for himself."
Southern Blood arrives September 8th.