Michael confirmed the incident Saturday but said in a statement he had been "stone cold sober."
Michael says he didn't want his fans or family "worried by what they are reading."
The Sun newspaper quoted the trucker, Lawrie Rowe, as saying the singer appeared dazed and confused.
Michael was banned from driving for two years in June 2007 after pleading guilty to driving while unfit through drugs. He was found slumped at the wheel of his car in north London.