The rocker battled alcohol and drug abuse for more than two decades, but is currently celebrating being clean for 18 months.
He tells The Sun online, "To be perfectly honest with you, I've been a very, very lucky guy.
"It really saddened me when I heard the news about George - there but for the grace of God go I.
"People have said, 'I used to feel sorry for George but I don't now because he had a liver transplant.'
"But they aren't really aware that alcoholism is a disease. It is very difficult to explain.
"An alcoholic will say to himself: 'I'm not that bad, Everybody else in the pub was drinking more than me.'
"But if you have one drink and it f**ks you up or 25 drinks and it f***s you up - you're still f***ed up."