The 36-year-old Kenyan has battled injuries over the past few years, which saw him win only one race in Chicago in 2016. He has warned his critics that his desire to win a maiden medal in London is still very much alive, reports Xinhua.
However, it will be no walk in the park for the two-time world marathon champion.
Last year he lost to compatriot Bedan Karoki in the final sprint and had to settle for fourth place.
"I have done well to show that I still have the energy and the tactics to win big city marathons," he said.
But there will be bigwigs in the starting line-up led by Olympic champion Eliud Kipchoge, who is seeking his third London Marathon gold after winning in 2015 and 2016.
"I have trained hard and deserve the credit and will continue to prove to my critics that I'm in the best shape of my life," Kirui said.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)