Michael fell ill last month while on his first concert tour in three years.
"I feel amazing. I mean, I'm very weak, but I feel amazing. I got a form of pneumonia and they spent three weeks keeping me alive," Sky News quoted Michael as telling reporters outside his home.
"I don't want to take you through all of it because some of it I want to protect my family from. But it was, basically, by far, the worst month of my life. But I'm incredibly fortunate to be here. And incredibly fortunate to have picked up this bug where I did because the hospital in Austria where they rushed me to was absolutely the best place in the world I could have been to deal with pneumonia. I have to believe that somebody thinks I've still got some work to do here."