The Briton, who achieved a magical "double double" at the Olympic Games by defending his London 2012 5,000 metres and 10,000m titles at Rio 2016, has now officially retired from track races.

He will be eyeing a strong showing at the World Marathon Major in the American city after a strong first full season on the roads.

That has seen him come third on home soil at the London Marathon in a British record time, but he faces strong rivals in Chicago.

The past three champions will all be in action with American Galen Rupp looking to defend his title on home ground.

Kenya's London 2012 marathon silver medallist Abel Kirui, the 2016 winner, and his compatriot Dickson Chumba, the 2015 winner, are also in the field.

However, Ethiopia's Mosinet Geremew, who set a time of 2 hours 4min 0sec at the Dubai Marathon this year, will start as the quickest man in the field.

His team-mate Birhanu Legese also set a lightning quick time in the United Arab Emirates city, stopping the watches at 2:04.15.

In the women's race, Kenya's Brigid Kosgei will be looking to go one better than her second-place finish last year, with Ethiopia's Tirunesh Dibaba not returning to defend her crown.

She recorded a personal best time of 2:20:13 to finish second in London this year, but three women in the field have gone faster.

Ethiopia's Roza Dereje has recorded 2:19.17, Kenya's Florence Kiplagat has managed 2:19:44 and another Ethiopian in Birhane Dibaba has run 2:19:51. 

Wheelchair races will also take place in Chicago tomorrow.

The inaugural Commonwealth Games Half Marathon Championships will go ahead as well in Welsh capital Cardiff.