SILVERSTONE, England, July 3, 2008 (AFP) - Jenson Button has thrown out a challenge to fellow British Formula One driver Lewis Hamilton that they swap wheels for their own feet and race a triathlon at the end of July.

The two men have often had fun chiding each other about who is the fittest and Hamilton, with a tongue in his cheek, said he unfortunately had nothing on on July 27 to prevent him taking up Button´s challenge in Bath.

Hamilton claimed Button had an advantage having already done a triathlon, but Button quipped that his compatriot´s McLaren car was much better than his Honda, so this evened things out.

"Anyway at the moment this (triathlon) is the only thing in which I´m competitive," Button joked, referring to his modest performances in Formula One this season.

The drivers now have three weeks to prepare for the race which comprises a 1.5km swim, a 40km bike ride and a 10km run one after the other.