Robbie Williams was miming to George Michael's version of Freedom when he filmed the video for his debut single - a cover version of the former Wham! star's solo hit.
The singer told Neil Fox in an interview on Magic 105.4 that he was drunk when he filmed the video which was made before he recorded the song.
He said: "And basically, the video to Freedom, I did all the lip-synching to George Michael's version because I hadn't recorded my version yet.
"And also I was in a bad, bad, way, I was pre rehab and I'd just finished off the top draw of the mini-bar, the whole top draw, all the liqueurs and spirits, and then started the video."
He admitted recording a cover version was "not the best start" to his solo career and said he was lucky the record company stuck by him despite a relative lack of success before the release of Angels "changed my history forever".
The song only made it to number four on the singles chart when it was released but has become a massive worldwide hit and one of the singer's best-loved songs.
Williams also discussed his recent wedding to Ayda Field which he said had given him "stability and happiness" and said re-establishing his once-troubled relationship with former Take That bandmate, Gary Barlow, was "in the stars".
He said: "To actually go from talking to Gary Barlow and not being sure about him and disliking him, to an hour later having my arm round him, creased up laughing on the floor in the kitchen because we're laughing so much at something he's just said, is a magical evening where a lot lifted."
He also told the DJ he was battling a mystery illness that left him "lethargic and depressed".
The star, who had fought well-publicised battles with addiction, revealed he recently discovered he had been ill for years.
He said: "I was lethargic and depressed and I thought I was lethargic and depressed as a person. I thought that was my make up.
"I found out a few months ago that I'd been ill, completely by mistake and I don't want to go into the whys and wherefores but what I had makes you lethargic and makes you depressed and I'd had it for years and not known and I'm on treatment for it. It's changed my life."
:: The full interview is on Magic 105.4 this Sunday between 2pm and 4pm.