They are all set to battle it out on the streets of London in April, but there is more to these Kenyan superstar runners than just pounding the streets over 26.2 miles. We caught up with both world-record holder Dennis Kimetto and reigning London champion (and course-record holder) Wilson Kipsang to find out more about their lives.
Five things you didn't know about Dennis Kimetto
1, He used to work as a farmer
Before becoming a world-beating marathon runner, 31-year-old Kimetto worked on his parent's farm. He told the Virgin Money London Marathon: "Most Kenyan boys do work for their parents. It was good and I really like farming. Sometimes I miss it, but I hope to be a farmer again one day."
2, He has helped to build churches and schools and funded young athletes
Kimetto has taken an active role in helping the community in his home country. He says: "It is my duty to give something back to the community. When I was just starting my running career others helped me. I think it is important to help each other as life can be very hard in Kenya."
3, He wore adidas Adios Boost trainers when he broke the marathon world record in Berlin. These have been worn for the fastest five marathon times in history (on record-eligible courses)
When Kimetto beat Wilson Kipsang's world record with a new time of 2:02:57, he was wearing what seems to have become the go-to shoes for elite marathon runners. He says: "The adidas shoes, especially the Boost, are bringing me a lot. I am very happy with adidas as my personal sponsor and the equipment they give me."
4, His wife passed out when he broke the world record
Caroline Chepkorir, Kimetto's wife, was so overwhelmed when her husband became the fastest marathon runner of all time that she fainted as he crossed the finish line. "It is true, they told me," he says. "When I came home she did not say but a few days later I was told and I asked her and it was true."
5, He loves football but his sporting hero is another marathon star
"I like to watch football on the TV, but athletics is where my heart is," explains Kimetto. He cites Paul Tergat, a Kenyan runner who held the marathon world record from 2003 to 2007, and won two Olympic silver medals in the 10,000m, as his hero.
Five things you didn't know about Wilson Kipsang
1, He's a former policeman
"It is always difficult for policemen to accept defeat. I think it is how we are trained. We have that passion to do things," the reigning Virgin Money London Marathon champion once said. He represented Kenya Police when he first began competitive running. After serving for three years he made the transition to professional athlete.
2, He owns a hotel in Kenya
Not just a hotel in fact, but a restaurant which serves African, Chinese and Indian dishes. They are part of the Keellu Resort Centre in Iten, the town where many elite marathon runners live and train. Athletes are regular visitors to the hotel and restaurant.
3, In November he did a parkrun with Dennis Kimetto in South Africa
To promote the launch of parkrun in South Africa, Kipsang teamed up with Kimetto to run the first ever Umhlanga event in November 2014. The 32-year-old told the Virgin Money London Marathon: "I see in Africa there are not many runners like in Europe or the USA, so I want to promote running for health in Africa."
4, He reacts very well to a challenge
During Kipsang's 2014 New York City Marathon victory, Lelisa Desisa tried to overtake him in the last minute and clipped his arm. The Kenyan star replied to the Ethiopian by saying "What's the problem?" before taking off and claiming the victory by four seconds.
5, He's a Chelsea fan and also likes Arnold Schwarzenegger.
Kipsang has a soft spot for the west London boys in blue but is yet to see a game at Stamford Bridge, saying "For sure it is on my wishlist". As well as Jose Mourinho, Lionel Messi and Ronaldinho are among his footballing idols. He says he doesn't read books and prefers to watch movies, particularly those of Schwarzenegger, to learn how to manage crisis situations. Like Kimetto, he also cites Paul Tergat as an idol.