LONDON, April 9 (Xinhua) -- The 2014 London Marathon Expo was officially opened on Wednesday by the running legend, and newly-crowned Guinness World Record holder, Haile Gebrselassie.

Thousands of runners are expected to follow the two-time Olympic champion down to the Excel Centre, Docklands, over the course of the next four days to collect their running numbers for the big race on April 13.

Speaking to the waiting crowds as he cut the red ribbon, Gebrselassie said: "My advice is to run behind me on Sunday.

"It is a great honour to be opening the Virgin Money London Marathon Exhibition and it's great to be back in London. You are all very lucky to be part of this marathon."

The Ethiopian, widely regarded as the greatest distance runner of all time, has broken the marathon world record twice in his long career, becoming the first man in history to run the marathon distance in under two hours four minutes. He will continue to test himself on the London course this Sunday when he runs as a pacemaker for the elite men's race.

"London has the best field ever competing on Sunday - the world marathon record holder, the world champion, the Olympic champion. It is going to be something big."

In honour of Gebrselassie's phenomenal career, Guinness World Records presented him with a certificate for the "Fastest run 20,000 meters", a track record he currently holds for running in just under one hour (56 minutes 25.98 seconds).