Documentary following the comedian as he pushes his body and sense of humour to the limit for Sport Relief by taking on the immense challenge of travelling to South Africa to run 27 marathons in 27 days to mark the number of years that his hero Nelson Mandela spent in prison. Cameras chart Eddie's gruelling, uplifting and hilarious journey through baking heat, high roads and hospitals - but can he make it to the final finish line?

• Claudia Winkleman