Usain Bolt has a new challenger, and maybe even a new distance to think about.
The biggest star in track is being sought out by Mo Farah for a charity race somewhere between Bolt's sprint specialty and Farah's distance domain.
Farah, who won the 5,000 and 10,000 meters at last year's London's Olympics, says "it'd be great to be able to do a distance where people vote in what distance will be suitable ... Bolt, are you up for that?"
Bolt seems to be considering Farah's challenge.
The Olympic sprint champion says "that sounds fun. It's going to be hard, but for me it's charity, so it's just all about fun and enjoyment."