The funnyman will race more than 700 miles (1,100 kilometres) across South Africa, stopping at important Mandela landmarks, over the 27-day challenge in aid of Sport Relief.

Izzard is set to begin the journey in Mandela's birthplace, before moving on to where he went to school, and famous spots including Robben Island prison, where he was jailed for 27 years, and finishing up outside the Union Buildings in Pretoria where Mandela gave his inaugural speech as President in 1994.

Izzard had previously tried to take on the challenge in 2012 but had to pull out due to health reasons. He also completed 43 marathons over 51 days across the U.K. for Sport Relief in 2009.

He says, "(This is) a salute to all who struggled and fought against Apartheid. So I am delighted to be doing this for Sport Relief. But of course - 27 marathons in 27 days is nothing compared to what Nelson Mandela did by serving 27 years in prison. He was a great soul and leaves a fantastic legacy for the world...

"I tried to do this four years ago and failed. This time I will succeed. But if I fail, I will come back again and again and again until I do succeed. Because that's what Nelson Mandela would have done."

The Eddie Izzard: Marathon Man challenge begins on 23 February (16) and ends on 20 March (16), and will raise money for disadvantaged people in the U.K. and around the world.

Mandela passed away in 2013, aged 95.