Sane, sober and surprisingly sentient, there's a world of difference between the lively 61-year-old rock legend spewing yarns in his London hotel suite today and the shambling comedy phantom that tottered and blundered through reality TV show The Osbournes.
His drug and alcohol intake has defined him over his 40 years in rock by prompting his most outrageous excesses – he's bitten the heads off bats and doves, tried to strangle his wife Sharon while in a blackout, urinated on the Alamo in Texas, clinically died after a quad bike accident in his back garden in 2003 (his heart stopped twice) and OD'd numerous times while under various influences.
All these events make his new autobiography I Am Ozzy a must-read for fans of vicarious rock'n'roll insanity, but a recent cleaning up has made him feel a million times more of a person.
"Some people never stop," he says, "like when George Best died, he had f***ing liver transplants, the whole nine yards, and he still continued to drink. Alcohol, drugs, tobacco, it's all the same, it's something to fix the way you feel, but it started to turn on me. As time went on my tolerance got bad, I could hardly hold anything, I'd drink and then have to have another drink to get me back up again, so by nine in the morning I was done.
"That was when I used to have a sniff of the old powder and get me back on my feet again. At first it was fun to do, but then it became not fun anymore and I had to do that just to get to what I thought was normal." A wide grin. "I'm becoming awake again now, you know?"
What were the wake-up calls? "One time we had a kids' party, one of the kids' birthdays, and Sharon said to me, 'You f***ing should have seen yourself yesterday,' and I went, 'What's wrong with me, I was all right, playing with the kids, whatever.' And she kept saying, 'Do you want to see yourself?' and she put a video in the machine and I was f***ing freaked out. I thought, 'Maybe it's true.'"
Osbourne's new-found sobriety makes this the perfect time to reflect on his more extreme behaviour: he really can now laugh at what, at the time, was truly terrible. For instance, during the early 1970s heyday of his former band Black Sabbath, he was regularly on the receiving end of death threats from both Satanist and Christian groups. "I've had numerous threats on my life. They were gonna shoot me one night. I go to this gig and there's this strange vibe going down backstage and all of a sudden this cop walks in and goes, 'We've had it from a very good source that this guy's gonna try and shoot you tonight, what do you want to do?' I went, 'Well, they're in so if I don't go on they're gonna get f***ing pissed off. They're not gonna shoot me when I'm onstage, I don't think'. I thought I'd just move around a bit more, use Tony my assistant as a shield."
Not that he didn't bring the wrath of the self-righteous upon himself, of course. On his early solo Diary Of A Madman tour in 1982, Osbourne would encourage his audience to fling offal, gore and meat onstage and would conduct the mock hanging of a midget.
"It was all in fun," he shrugs. "He'd say, 'Where's the f***ing toilet, Oz?' and I'd come over and put my hand over the WO and go, 'Look, MEN'. But he couldn't open the door to get out so women would be smacking him around. It's sad because he committed suicide, he overdosed on Prozac."
Such gruesome theatrics saw Osbourne branded as a hard rock relic as the new wave of edgy emo and metal acts exploded in the 1990s, making him an unbookable headliner in the eyes of the festival promoters. He bit back by starting his own annual travelling festival, Ozzfest, which has now enjoyed 13 sold-out years and given rising acts such as System Of A Down, Slipknot and Linkin Park a leg-up.
"I've often had people go, 'I bet you're happy with the resurgence of heavy metal.' Well number one, I can't stand the title, heavy metal. If it was heavy rock it'd be better. But you can't say that the bands now sound anything like the bands in the 1970s. But what I'm happy about, I gave a platform for a lot of these kids to do gigs. The record industry is f***ing dying, so what a lot of these kids will do is have a recording thing on the bus and make a record through the night as they're travelling and sell it at the gig."
Panto-metal pioneer and modern rock benefactor, it's ironic that Ozzy is still most widely infamous for his bewildered and profane performance as a hell-bound Homer Simpson in The Osbournes. It's an experience he wouldn't repeat. "It was an experiment. I looked at it being an extended version of Cribs, that's basically what it was. Believe me, we could have gone on with it. I didn't want to do it. I haven't really watched any of the shows, I've seen bits of it. I can't stand to see myself on TV. They're very ruthless people, it's a very cut-throat business."
And the strangest thing he's snorted? "Snuff in a pub. A quick line of snuff, the next minute I coughed and a big f***ing black bubble of shit come out of my mouth. I thought my f***ing brain had melted." On the contrary. Of all the cerebral mulches in rock, it's amazing that Ozzy's is still very much intact. v
I Am Ozzy is published by Sphere