If Lel is to match the achievement of previous three-time winners Dionicio Ceron (1994, 1995 and 1996) and Antonio Pinto (1992, 1997 and 2000) he will have to overcome a tough field.
Olympic champion Stefano Baldini of Italy and Lel's compatriot Luke Kibet, the world champion, have been confirmed for the race, along with former world record holder Paul Tergat and 2006 winner Felix Limo.
"I believe this is one of the best fields we've ever assembled," said race director David Bedford.
"I am delighted to welcome Martin back to London. He has a fantastic record here and will be extremely hard to beat.
"But it will not be easy for him as the opposition is of the highest quality and many of these stars will be hoping to prove their fitness before the Olympic Games in Beijing."