His deep voice in the recording is unrecognisable from the familiar high-pitched one which propelled him to superstardom.
He is heard telling his doctor, Conrad Murray, that his upcoming comeback concerts had to ‘be phenonmenal’.
The singer, who died a month later, adds: ‘When people leave my show, I want them to say, “I’ve never seen nothing like this in my life, Go. Go. It’s amazing.”’