Fame rests lightly on the neatly braided head of David Haye. It is four months since he tamed the hairy-backed monster from St Petersburg to become Britain's first world heavyweight champion in a decade and while he admits that life has changed, he insists he hasn't – despite becoming one of sport's most celebrated figures. His charm, chat and chutzpah continue to endear him to audiences well beyond the boxing ring. "It's much more difficult getting around," he admits. "I'm always signing autographs and I keep getting stopped by these little old ladies who say, 'Aren't you David? You beat Goliath'."
Since that impudent victory over the 7ft, 23-stone Nicolay Valuev in Germany, there have been scores of offers for his promotional services, mostly for charity, including one from Cherie Blair and another from Naomi Campbell. "I suppose I am more of a name now after the Valuev fight, a lot of people want a piece of me," he says. "I get to a lot of dinners and charity dos and it's all fun. I do whatever I can, and if you can raise 10 grand or so for a particular charity it makes you feel good. It's easy not to do stuff like that but it's also just as easy to do it."
David Cameron's office have also called to ask if he would endorse some of the Tories' sports initiatives. He hasn't decided yet as he is focused only on the first defence of his World Boxing Association belt, which he makes next Saturday at Manchester MEN Arena against the mandatory challenger John Ruiz, a tough old nut who seems to have been around for ever. "Now I have become champion there is a different spin," he says. "I can't let everyone down. And the last thing I want to be known as is a one-hit wonder. Valuev was a bit of a freak show but this guy Ruiz is big and strong and tougher than him.
"I expect to hit him a lot but the one thing he's shown throughout his career is his durability. He'll just keep steaming through. He's got some good names on his resumé like Evander Holyfield, Hasim Rahman and Roy Jones, and you don't beat them guys if you're no good. I owe it to my fans and Britain not to lose. A loss would kill me, it really would."
Riding on the result is a fight with one of the Klitschko brothers, the Ukrainian giants he has insulted and infuriated yet failed to take up the options to face either. He claimed a back injury when due to meet the younger sibling, Wladimir, and pulled out of a match with Vitaliy when the Valuev bout was offered.
Between them the Klitschkos hold the IBF, WBO, IBO, WBC and Ring heavyweight titles. Wladimir dismisses Haye as a "smart-arse", adding: "He has promoted himself smartly but we need to see some action from him." Haye promises that will happen once he has dealt with the 38-year-old warhorse Ruiz, an American of Puerto Rican descent, a former WBA champion who has been beaten eight times in a 54-fight career, with one draw and 30 knockouts. He has twice lost to Valuev.
There is also a possibility that Haye may have to fight Valuev again, because there was a return clause in the contract, but he says: "I'm not thinking about the next fight after this. Once Ruiz is out of the way we'll sit back and look at the heavyweight landscape. Wladimir won his fight [against Eddie Chambers] last week and if Vitaliy wins his next one [against European champion Albert Sosnowski], fingers crossed, I can meet and beat both. That's the plan.
"The Klitschkos hate me and it's not just because of that T-shirt stuff. They know I'm not scared of them. Where I grew up in south London it's not wise to be scared of anybody. I'll always say what I can to get under their skin. People may cringe at some of my stunts [such as knocking the head off a cardboard cutout of Valuev] but I don't mind making myself look a twat for £5 million.
"Of course I'll try and blast Ruiz out, and hit him with some flurries that he's never been hit with before, but this could be a long fight – the sort of in-and-out tactics I used against Valuev won't work against Ruiz. This guy's a lot smaller so he'll be there in front of me. I'll have to go back to doing what I do best, attacking from all angles. He's not the sort of opponent I would have picked for my first defence, he's got a style it's difficult to look good against. He tucks in, comes in heavy with his head and his elbows, he's dangerous, dirty and awkward."
Some 18,000 tickets have been sold at the MEN, the fastest-selling fight there since Ricky Hatton met Kostya Tszyu. For this contest Haye has forsaken his home and training base in northern Cyprus, and prepared at a state-of-the-art gym under a railway arch in Vauxhall, south London, spacious enough for his manager, Adam Booth, to park his Jag at the ringside.
There we chatted over Haye's lunchtime plate of grilled chicken breasts and raw vegetables. "That's about as exciting as my meals get at the moment," he grins wryly. "What I really look forward to after the fight is stuffing my face with chocolate – about a kilo of it. I'm a chocoholic. I'll stuff myself with it until I'm sick, because I haven't had any for a couple of months." There is something else he hasn't had for a couple of months. Sex. He believes in old-school abstinence, lucidly explaining: "When you ejaculate you lose part of your soul – it's what the Chinese call Chi, the life force, the energy that is held in men, and the man is more vulnerable after he has had sex. Most people want to roll over and sleep. This isn't the feeling you need when you fight, you need to be 100 per cent focused."
Haye has always said he will retire by the time he is 31, and that birthday will come around in October next year. "Nothing's changed," he says. "I've said that since I was 10, that I'd be heavyweight champion and retire by the time I was 31.
"I am financially stable and I am not boxing just for the money but for the achievement. My bills are all paid – this is about my legacy. There's nothing really that me or my family [he has a wife, Natasha, and 22-month old son, Cassius] really want that we haven't got. I am happy I can provide quite a good life for them, that's the bottom line. There's nothing I want to buy that I haven't got already. I'm not a big spender and, anyway, how much money can one person spend? I've got a few cars [a Mercedes, a Range Rover and a Bentley] and that's about it." There is also his villa in Cyprus and a house in Brixton.
Behind the flashy public persona, the one-time wild child of the luvvie circuit is a private family man. "Cassius is almost two. My one regret is that I can't spend as much time with him when I am in training. I enjoy being a father. I also miss the quietness and tranquillity of Cyprus – no one knows who I am over there."
The Hayemaker's idol is Lennox Lewis: "Even if I beat Ruiz and then knock out both Klitschkos it would still be hard for me to say I was better than him. I don't like to be compared with him because we are completely different fighters, I am a lot smaller and there isn't the depth of heavyweights now that there was when Lennox was around.
"Everyone knew Tyson, Ali, Frazier, even Larry Holmes. Americans used to dominate heavyweight boxing, but now we have Eastern Europeans with names you struggle to pronounce. At least now I'm champion everyone can pronounce David Haye."
The likelihood is that the one-paced, one-dimensional Ruiz, although not as pedestrian as the lumbering Valuev, will still be too slow for a souped-up Haye whose speed has been sharpened since the Valuev fight by tips from his new friend Usain Bolt and track sessions with Linford Christie at Brunel University. He has also recruited a fitness coach from athletics in Reuben Tavarez, a 400-metre hurdler who is coached by Christie.
Otherwise his small entourage has remained more or less the same since he turned professional after winning a world amateur silver medal. "I've said it from the very start. I'm not in the game to make friends, inside or outside the ring. I've got enough friends and now that I've got the belt I don't need any new ones.
"I enjoyed all the glory of becoming world heavyweight champion and the parties, but after a month I was itching to get back in the gym because this is what I do. I've been training from a young age and I'd be down the gym while my mates would be out having a laugh – shagging or whatever – but those are the sacrifices you have to make.
"I suppose it was a boring life, but when I am not training I do let loose a bit. But I go about my business with no stress or drama. This game is simple. Win titles, make as much money as possible and get out with as many faculties as possible. That's it."
Haye v Ruiz is live in high definition on Sky Box Office