Phil Lesh, one of the founding members of rock group The Grateful Dead, has been diagnosed with prostate cancer.
Lesh has urged fans to be organ donors since his own liver transplant
The bassist, 66, will have surgery in December and has said he expected to have "a rapid and complete recovery".
In a statement on his website, Lesh urged all men to take regular tests to detect the disease, telling them: "You may save your own life."
The psychedelic band, which formed in 1965, split 30 years later following the death of frontman Jerry Garcia.
Lesh was with them throughout this time - and also joined the group's other surviving members for a reunion tour of the US in 2003.
He had a liver transplant eight years ago and said that since then, his health had been monitored "by a crack team of doctors".
His diagnosis had been made at an early stage, meaning the cancer was "small and slow-growing".
"I am feeling energetic as always and all my scheduled appearances will occur as planned," said the star, who performed at the Vegoose Music Festival in Las Vegas on Sunday.