The 'Bodies' singer checked into rehab on his 33rd birthday in February 2007 after realising he was 'physically and mentally ill' from years of taking painkillers and anti-depressants.

Speaking about his three-week stint at the Meadows treatment centre in Arizona, Robbie said: "It was damn serious. Robbie Williams does not go into rehab just if his life gets a bit out of control. It was damn serious. Death had to knock on my door to help me with my decision."

The former Take That star – who was smoking 60 cigarettes a day and downing 36 shots of espresso coffee when he went into rehab - admits he constantly lives in fear of a relapse but refuses to let it ruin his life.

He told Germany's Stern magazine: "I have a self-destructive character but does this hold me back from being happy? No."

One of his reasons for the troubled singer's newfound happiness is girlfriend Ayda Field, who has helped the 35-year-old singer turn his life around.

He said: 'A friend said, 'Robbie, I know a woman who would be perfect for you,' and he was right.

'She didn't try to change me and just like that, she changed me for the better. I am a very happy man at the moment. I'm now in love with someone who returns this love as strongly as I love her. I've never experienced that before.

'That's what makes me so careful in this relationship, because I don't want to hurt Ayda.'

Robbie and Ayda, 30, have been dating for two years and recently moved back to the singer's native UK from Los Angeles ahead of the release of his new album 'Reality Killed The Video Star'.