Eddie Izzard plans to run 27 marathons in 27 consecutive days as a tribute to former South African president Nelson Mandela.
The comedian and actor’s challenge will be filmed for a documentary set to be screened by Sky later this summer.
The marathons, which will geographically trace Mandela’s life in South Africa, are intended to represent the 27 years the former president spent in prison between 1962 and 1990.
Izzard’s marathons will begin in the Eastern Cape of South Africa where Mandela was born and will pass through Pretoria, where he was tried, and Robben Island, where the 93-year-old spent much of his time imprisoned.
Proceeds raised from the challenge will be donated to the Nelson Mandela Foundation and other South African charities.
“Everywhere that resonates with his life, we are going to run” said Izzard, 50.
"Maybe you'll get this visceral relationship between the struggle of 27 years and the struggle of me trying to run marathons."
However, Izzard admitted that he didn’t expect to meet Nelson Mandela himself during the challenge.
“I've already had the honour of meeting Mr Mandela... “ he said. “I don't want to bother him."
He added: "If someone says to him: 'By the way, there's an idiot - you've met him before - he's doing these runs,' hopefully he might go: 'Oh, yes, running is a good idea. That is a positive thing.'
“Or he might say: 'He's crazy.'"
This is not Izzard’s first long-distance running challenge for charity. In 2009, he completed 43 marathons over 51 days to raise funds for Sport Relief.