Don't let me down: Calzaghe fears he'll suffer the same fate as Hatton if his fans abuse US anthem

But the pride of Wales has one concern on his mind.

Right at home: Joe Calzaghe is enjoying life in Las Vegas

'I really hope my fans don't spoil the American national anthem,' he said. 'It really could lessen my chances.'

Calzaghe was in the crowd in December when rowdy followers of Ricky Hatton caused outrage by booing and whistling during the singing of The Star Spangled Banner. Their behaviour prompted fears that disrespect for the American anthem may have contributed to referee Joe Cortez's controversial handling of Floyd Mayweather's victory.

Calzaghe said: 'It was a stupid thing to do. You're in someone else's country, you've got an American referee and American judges and, let's be honest, it's not doing the fighter any good, is it? I don't want them to lessen my chances. Joe Cortez is the ref and I don't want to upset him.

'I'm going to bring thousands over and you have to say that British fans are the best in the world. No other country could get people to travel halfway round the world to support their boxers in the numbers we do. Mayweather and Hopkins would be lucky to get 200.

'I want to repay them by boxing my heart out and coming away with a win. But I don't want a repeat of what happened with Ricky. It was only a minority. I was in the arena and there were a lot of Britons who, like me, were disgusted.'

Ten miles from the 24-hour action on The Strip, Calzaghe was quietly bringing his preparations to their peak in the secure haven of a gated community. Inside the millionaire's mansion, his uncle, Sergio, was rustling up pasta for lunch, while his father and trainer, Enzo, fielded a continuous stream of media calls and sparring partner Nathan Cleverly wandered in looking for food.

Every morning Calzaghe has been running seven miles around the jogging trail on the complex in pleasant 70 degree temperatures as he adjusts from the cold of South Wales to the thin desert air. Afternoons have been taken up with his final sparring sessions at an out-of-town gym.

Only five pounds over his lightheavyweight limit of 12st 7lb, he claims to be in perfect shape for making his American debut at the age of 36.

Still unbeaten in 44 fights over 18 years, Calzaghe has unshakeable belief in his superiority over the brash 43-year-old Hopkins.

Yet he knows that, in the murky world of boxing, nothing is certain. 'If the fight was in Wales, it wouldn't even be a race,' said Calzaghe.

'But the difficulty for me is that I'm fighting outside my comfort zone, in America and with American judges.

'He is a Golden Boy fighter and a partner in the company [promoting the bout] so if it's a scruffy fight I could win 60-40 and still get done. If I underperform and fight his fight, I could get ripped off. I have to dominate, and I will.'

Calzaghe is disdainful of Hopkins, in particular his attempts to undermine the Welshman's successful partnership with his father by claiming that it betrayed emotional weakness. The Calzaghes are fiercely proud of each other and both their stories are inspirational. But boxing is strictly business.

'If it wasn't for my Dad, I wouldn't be in boxing,' said Calzaghe. 'We've come through a lot of challenges and even when some people wanted me to get rid of him I stuck with him. Now he's got his own identity. He's not just Joe's Dad any more. He had three world champions in a tiny gym in South Wales and was named the 2007 Trainer of the Year. How brilliant is that?'

This weekend the Calzaghe clan will be extended by the arrival of Joe's sons, Joe Jnr, 13, and Connor, 10, to lift the home-loving boxer's spirits yet more.

Concentrating on speed-work, he will train right up to the day of the fight, ready for the toughest test of his career and, at more than £5million, his biggest ever pay-day.

'It's been a struggle to get this far and I feel I have paid my dues,' said Calzaghe. 'I feel like I'm now being repaid for my dedication, hard work and talent.'