Defending champion Martin Lel will aim to make history with a record fourth win at the London Marathon next April.
The 30-year-old Keynan, who won the race in 2005, 2007 and 2008, will also be looking to match Dionicio Ceron's achievement of three consecutive wins.
He will face stiff competition in the race on 26 April after the line-up of the men's elite field was confirmed.
The top four finishers from last year's race and all three Beijing Olympic medallists will also take part.
Lel's 2008 winning time of two hours, five minutes, 15 seconds made him the fourth-quickest marathon runner ever.
"It's wonderful to be coming back to London," he said.
"I have great memories from my last three victories and will be doing my best to put my name in the record books with a fourth win."
One of his biggest rivals will be compatriot and Beijing gold-medal winner Sammy Wanjiru, who finished second in London this year, nine seconds behind Lel.
606: DEBATEAbderrahim Goumri and Emmanuel Mutai, who finished third and fourth in London this year, will also be challenging, as will double former world champion and Olympic silver medallist Jaouad Gharib and Beijing bronze medallist Tsegaye Kebede.
There are also two former London winners in the line-up - 2002 champion and former world record holder Khalid Khannouchi, and former world champion and 2006 winner Felix Limo.
"With 11 men who have run faster than 2:08 this is probably the highest quality field we've ever assembled for the men's race," said race director David Bedford.
"In particular, we are delighted to welcome back our reigning champion Martin Lel and the Olympic champion Sammy Wanjiru whose performance so delighted us this summer.
"But with such tough opposition they will have to be at their very best to win the 2009 London Marathon title. It's a mouth-watering prospect."
The 2009 men's elite field and best times:
Martin Lel (Ken) 2:05:15
Sammy Wanjiru (Ken) 2:05:24
Abderrahim Goumri (Mor) 2:05:30
Khalid Khannouchi (USA) 2:05:36
Felix Limo (Ken) 2:06:14
Emmanuel Mutai (Ken) 2:06:15
Tsegaye Kebede (Eth) 2:06:40
Hendrick Ramaala (SA) 2:06:55
Jaouad Gharib (Mar) 2:07:02
Viktor Röthlin (Swi) 2:07:23
Yonas Kifle (Eri) 2:07:34
Tessema Abshiro (Eth) 2:08:26
Dathan Ritzenhein (USA) 2:11:06
Zersenay Tadese (Eri) debut
Hicham Bellani (Mor) debut
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