Kenya's Eliud Kipchoge will again target the mythical two-hour marathon barrier in a special race to be held between late September and early October, likely in London.
Kipchoge went close to smashing the barrier when he came in 25 seconds off the mark in a staged race around Italy's Monza race circuit in 2017.
"Running the fastest ever marathon time of 2:00:25 was the proudest moment of my career," Kipchoge said.
"To get another chance to break the magical two-hour mark is incredibly exciting. I always say that no human is limited, and I know that it is possible for me to break this barrier."