The ‘We Made You’ rapper relapsed in 2005 following an unsuccessful stint in rehab for an addiction to sleeping medication when a friend gave him a handful of unidentified blue tablets.

He said: "My doctor told me those mysterious new pills were methadone, which is used to wean heroin addicts off dope. Had I known it was methadone, I probably wouldn't have taken it. But as bad as I was back then, I can't even say 100 per cent for sure.

“My doctor told me the amount of methadone I'd taken was equivalent to shooting up four bags of heroin. Even when they told me I almost died, it didn't click."

The 36-year-old hip-hop star admits his substance abuse addiction had spiralled out of control by then.

He added to Vibe magazine: "It's no secret I had a drug problem. If I was to give you a number of Vicodin I would actually take in a day? Anywhere between 10 to 20. Valium, Ambien, the numbers got so high I don't even know what I was taking. I started looking around my house to see if I had a stash box of Vicodin. I'm ransacking my house, finally find something in the basement, in a little napkin, seven and a half Vicodin - the big extra strength ones - and a few Valium."

Following a three-year-break from recording material, Eminem is thrilled to be back with his new LP ‘Relapse’ and insists he is only addicted to work these days.

He said: "I almost feel like a little kid again with rap. I want to play around with different flows. If I don’t feel like it's what I'm fully capable of, if there's one weak line, I want to change it. Rap was my drug. It used to get me high and then it stopped getting me high. Then I had to resort to other things to make me feel that... now rap's getting me high again."

‘Relapse’ is due for release in the US on May 19.