Recent comments made by Lewis Hamilton about the fitness of fellow English driver Jenson Button led to the Honda ace throwing down the gauntlet today.

Rather than discussing tactics and reflecting on previous races, the official FIA press conference was the scene of a sort of 'Superstars Challenge' as Button offered to take on Hamilton in a triathlon.

As the two drivers squared up - all in good fun - Scottish veteran David Coulthard added to the mix, offering to act as referee.

However, any hope of Button and Hamilton going head-to-head later this month (27th), has been killed off by the McLaren driver's father, who said: "Lewis accepted the challenge like the good sport he is and in the spirit with which he accepts things.

"But unfortunately for Lewis we are withdrawing him from this," he added. "We are in the middle of a championship and that is the focus of our attention."

At promotional event for Reebok earlier this week, Lewis Hamilton suggested he was fitter than Button. Consequently, when the subject was raised today, the McLaren driver replied: "I've noticed that Jenson has a bit of a belly and so... I'm only joking! I was just trying to be positive."

"They're called muscles," the Honda driver hit back.

Asked about the recent triathlon Button contested, Hamilton said: I'm not sure whether I could do a triathlon, so I'm not going to say that I could beat him at that. But generally I work my arse off... you work your arse off to be fitter than me, and you've got to believe that you're fitter than me and the same way the other way."

"I do believe..." said Button.

"It would be good to have a challenge," said Hamilton

"I'm sure we can work something out," Button replied. "If you don't like triathlons... The good thing is that you've got three different activities. I've got a triathlon on July 27th if you're interested."

However, knowing that his diary is filled with promotional events, Hamilton admitted that it might be difficult to find the time, though some might see this as the youngster getting 'cold feet'. Eventually, it was Coulthard who took control: "He's throwing down a man challenge," said the Scot, "you can't turn down a man challenge."

Informed that the triathlon, which would take place in Bath, involves "1.5 kms swim, 40 kms bike and a 10 kms run", Hamilton said: That's not too bad.

He then continued: "I was just checking my calendar, so I wasn't being rude. I was trying to see whether I'm busy that day and unfortunately I don't think I am. No, honestly, the biggest incentive is, if I do beat you, then you've got some money for a charity which is great. However, you do have an advantage as you've already done one, and I already know that by doing one you're better the next time. But man, I'm up for it, I'm up for it."

Alas, Lewis' father clearly isn't.