American legend Michael Johnson believes that Usain Bolt is the man to break his 400m world record, an achievement he believes will cement the big Jamaican's status as an athletic legend.

Johnson, whose 43.18 remains the best-ever time in the one-lap event, endorses Bolt's 400m consideration, after the 100m and 200m world-record holder told journalists in Monaco several weeks ago that he wouldn't mind adding the 4x400m to his 100m, 200m and 4x100m Olympics 2012 schedule.

Bolt's coach Glen Mills has since poured cold water on his charge's intentions pointing out that his athlete would have to run the 400m and finish in one of the top spots at Jamaica's Olympic trials in June in order to qualify outrightly for the mile relay team. With no plans in place for Bolt to run the 400m at the trials, the decision to include Bolt would rest squarely with the Jamaica Athletics Administrative Association. To sum it up, it's highly unlikely that Bolt will be chasing four gold medals in London next summer.

Johnson - the first man to win the 200m - 400m double, himself warned Bolt about the dangers of such a pursuit not too long ago, however, he now seems to have a change of heart.

"He was a 400m runner before he was a 100m and 200m runner," he told ESPN. "He has always been great as a 200m runner but he was a good 400m runner when he was very young."

American Carl Lewis was the last man to win four gold medals at the Olympics, after his exploits at the 1984 Los Angeles Olympics.

under 43 seconds

"He has the build to be a great 400m runner and he certainly has the speed. Without a doubt, I think if he chose to make the switch at some point in his career and decided he was going to train for the 400m, I am certain he would break the world record and probably run under 43 seconds and become the first person to run 42 seconds," Johnson added.

"I've heard all types of rumours, whether he is going to run 400m or 4x400m relay, I think obviously he's the best sprinter in the world, he's the best there has ever been," Johnson added. "He is an incredible athlete and I think he will be focused and ready to go next year to defend his titles at 100m and 200m which he has said he wants to do and (Jamaica) have the best 4x100m relay in the world at this point.

"Beyond that anything else is just speculation and I think we will just have to wait to see if he decides to do anything else. But I think he is in a great position to repeat (2008), and I wouldn't put my money on anyone else but him for 100m and 200m," Johnson noted.