The Kenyan broke the world mark at the Berlin Marathon last year.
There is $500,000 World Marathon Majors title is on the line.
The winner will net $500,000.
The race is chock full of former champions, Olympic champions and course record holders.
The 35-year-old suffered a broken toe during a training run over the summer.
The Ugandan marathoner received it for Olympic sportsmanship.
He was the surprise winner in the British capital last summer.
The Ugandan gold medalist is gearing up for the London Marathon.
The car he was traveling in swerved off the road, but he was able to avoid injury.