Follow the story of David Walliams' extraordinary efforts to swim across the English Channel for Sport Relief in a very special BBC One documentary.
Walliams trained for a year for his remarkable Sport Relief Super Swim
Sport Relief presents 'Little Britain's Big Swim' will be shown at 2000 BST on Thursday 13 July.
We go behind-the-scenes to see the comedian's punishing 10-months of exhausting training for the attempt.
Little Britain co-star Matt Lucas provides the voiceover as we share all the highs and lows along the way.
Walliams successfully completed the 21-mile swim across the English Channel to France on Tuesday 4 July.
The 34-year-old comedian, who entered the water at Shakespeare Beach in Dover, Kent, at 0531 BST on Tuesday, reached France at about 1600 BST.
He had expected the crossing to take 14 hours, so was "relieved and pleased" to make it in 10 hours and 30 minutes.
Walliams undertook the gruelling swim as part of Sport Relief, and so far he has raised £587,860 for the charity.
But you can help him raise even more, and recognise his amazing achievement by going to his website and donating some money.
Alternatively you can congratulate him by texting DAVID to 82125 (texts cost £1 with at least 70p going directly to Sport Relief.
During the crossing, he had to swim through shoals of jellyfish, and cope with water temperatures as low as 15C.
After his epic swim, Walliams told BBC Radio 1 he had completed it much faster than he thought he would.
"I thought it was going to take me about 14 hours - well, if I was going to get there.
"I feel relieved because we needed a happy ending to this story. I feel it's taken the sting out of the World Cup."
The comedian spent the last year training with former Olympic modern pentathlete Greg Whyte.
Whyte described swimming the channel as "one of the toughest physical challenges on the planet".
Fewer than 10% of people who have attempted to swim the Channel have succeeded.
The famous stretch of water is one of the world's busiest shipping lanes, with 600 tankers and 200 ferries crossing it every day.
Walliams covered himself in goose-fat to keep warm and was being given food from a pole on his support boat during the swim.
The full story of Walliams' exploits will be told in a BBC One documentary at 2000 BST on Thursday 13 July.
Sport Relief Saturday is on July 15th when tens of thousands of people will be raising money by completing a Sport Relief Mile.
The idea is for as many people as possible, of all ages and abilities, to complete a mile and raise money for Sport Relief.