Double Olympic gold medallist Mo Farah will make his debut in the London Marathon this year, but says he will only run half the race.
The 29-year-old Briton said he intends to cover half the 26.2-mile distance, in what will be a warm-up for the following year, when he plans to keep going until the finish line.
"I will make my marathon debut in the 2014 London Marathon, but will run the 2013 race to half way as part of my preparation for 2014," said Farah.
"It will allow me to understand the course and the systems I will need when I run the full distance. To run as the double Olympic champion makes it even more special. It will be my pleasure to run my first marathon in London."
However, Paula Radcliffe, who won the women's race in London in 2002, 2003 and 2005, questioned Farah's decision.
"Honestly, I find it a little bit strange," said Radcliffe. "It's not what I would have done. Either you find a good half-marathon somewhere or you take the plunge and attack the distance and race it.
"Here he's caught between two stools. For me, you go into the London Marathon when you're ready to do it and attack it hard. But everybody has different reasons."
Farah, who won gold in the 5,000m and 10,000m at the 2012 London Olympics, said he may also move up to marathon at the 2016 Games in Rio.
He begins his season with a 3,000m indoor race this weekend at the British Grand Prix in Birmingham, before flying to New Orleans to compete in a half-marathon.
Running half the distance in London this year "will allow me to understand the course and the systems I will need when I run the full distance", said Farah.
"I am excited and looking forward to it," he added. "You've got to go and test yourself to see what you can do."
As a schoolboy, Farah won the junior event three years in a row between 1998 and 2000.
"I won the London Mini-Marathon when I was younger, and have watched the race every year for as long as I can remember," he said.
"As a young boy growing up in London it has always been my ambition to run the London Marathon. It's one of the biggest marathons in the world. It will be my pleasure to run my first marathon in London.
Alongside Farah in London, this year's men's field will include world record holder Patrick Makau, Olympic champion Stephen Kiprotich and world champion Abel Kirui.