Walliams dives in for Thames swim
Little Britain star David Walliams set off today on his most dangerous challenge so far - swimming the entire length of the Thames.
The comedian and panel show host is raising money for Sport Relief by swimming 140 miles over eight days from Gloucestershire to London.
Hundreds of wellwishers lined the river bank at Lechlade to give Walliams a loud send off and before taking the plunge into the icy river, he spoke to many of them
The comedian said that when the swim got really tough, he would think about how the money he raised would help some of the poorest people in the world.
"I think about happy things, I think about what I'm going to eat when I get out," he said.
"I think about songs and I have been on some trips with Comic Relief and Sport Relief and I think about the people the money raised will help.
"I met this boy in Kenya on the street. His name is Philip and he's 12-years-old and he's been homeless for four years.
"His mum and dad are dead and he lives in desperate circumstances.
"Sport Relief funds a centre that gives him education, food, shelter and healthcare.
"I think about him because he is such a sweet boy, with so much hope.
"I said 'what do you want to be when you're older?' and he said he wanted to be a pilot.
"He's living in the most desperate circumstances yet he still has great aspirations.
"I think about him and not wanting to let him down."
Walliams described himself as a "masochist" for wanting to do another swimming challenge.
"I must be a masochist. I wanted to do something else and I'd just turned 40 and I thought I haven't got much time left because my body is falling apart," he said.
"I thought I better get on and do something because one day it's going to be too late."
Walliams said this swim would be 120 miles longer than swimming the English Channel.
"That's the scary thing. It's all right to be full of bravado today but this is day one of what will probably be eight days of swimming," he said.
"So that's what really scares me, the mental challenge of days five, six and seven.
"It may be a bit easier when the end's in sight but I just worry about the middle bit when it's going to be lonely and a bit boring.
"The nice thing about this, as opposed to the Channel, is the people can come out and see you.
"And seeing this part of the country. People think of the Thames as being London but it's about 120 miles until you get to Teddington Lock."
Walliams said he had not thought about what he might do next but was considering hanging up his trunks.
"The day after I swam the Channel people said 'what are you doing next? Do you want to go up Everest?'
"I think I should hang up my trunks after this. I haven't thought about the next challenge, I feel this is enough.
"There's swimming the Atlantic but that's too hard. I looked into it and it's 3,000 miles and will take about six months - by which time people will have completely forgotten about you."
Walliams said that if he did take the swimming plunge again, comedy partner Matt Lucas was unlikely to join him.
"We've done a lot of things together for Comic Relief," Walliams said.
"It's not his sort of thing. He's not a great fan of swimming, so I'm not sure he'd enjoy it."
Walliams's swim will also see him brave bitingly cold river water, which can cause cramp and involuntary breathing spasms known as a "gasp reflex".
He will battle powerful and unpredictable currents and undertows and will burn the equivalent of 4,400 calories every day.
As well as navigating the busy river traffic, David will have to deal with murky water that harbours a cocktail of bacteria such as E.coli, salmonella and hepatitis.
Walliams will also have to avoid the 39 million cubic metres of raw sewage that finds its way into the Thames every year after heavy rainfall - and swans.
"When I got here last night there were about 30 swans and I have been attacked by swans in the training, so I am actually quite nervous about them," the comedian said.
"When they're coming towards you fluffing their wings and hissing when you're in the water, it's quite scary."
The BT Sport Relief Challenge: Walliams vs The Thames will be filmed for a documentary to be broadcast in the build up to the Sport Relief weekend in March next year.
Walliams is no stranger to getting wet for a good cause - in 2006 he swam the Channel, raising £1 million in aid of Sport Relief.
He has also swam the Straits of Gibraltar, and last year cycled from John O'Groats to Lands End, also for Sport Relief.
Walliams is asking for people to sponsor him at www.sportrelief.com/walliams.
As well as making a donation, he could do with some encouragement and hopes the members of the public will come to the riverside and cheer him on.
People can check out the GPS tracker online and follow the Twitter feed using hash tag #Thamesswim to see where he will be.