Speaking to Smooth Radio's Mark Goodier, the 47-year-old singer revealed that he started to smoke again after he was sent to prison.
He said: 'When they put you inside, they almost chuck nicotine at you and, having given up regular cigarettes many years ago, I found that within a week I was hooked back on the nicotine.
'What I have found is that now I am trying not to smoke cigarettes, the tweeting stops me from doing it because I've got something to do.”
He added: “Instead of having to have one of those plastic things in your hand that you suck on, I'm just tweeting to stop myself from smoking cigarettes now.'
The former Wham! star was jailed for driving under the influence of drugs last year and served a month in prison, after he crashed his car into a Snappy Snaps shop on Hampstead High Street, in London.