Although he has spent years since he became clean and sober raising awareness and millions of dollars to help those affected by the disease, he said he still feels guilty about his actions as a younger man.
He talked about his misspent young adulthood while promoting his memoir, "Love is the Cure: On Life, Loss and the End of AIDS" in a two-part "Today" show interview to air Tuesday and Wednesday on NBC.
"I wasted such a big part of my life, when this epidemic was beginning to happen in the early 1980s. And I was a drug addict and self-absorbed," John said. "You know, I was having people die right, left, and center around me, friends. And yet, I didn't stop the life that I had, which is the terrible thing about addiction. It's that -- you know, it's that bad of a disease."
Asked if he feels guilty about his actions, John said, "I do."
Pressed about whether he thinks he has since made up for it with all of his charity work, John replied: "I'm making up for it. There is so much more to be done."
Celebrity Families of 2014 [PHOTOS]