David Walliams swim: Behind the scenes

David Walliams raised over £1m by swimming 140 miles of the Thames in eight days for Sport Relief.

Now a behind the scenes documentary looks at the highs and lows of his gruelling challenge.

Walliams told BBC Breakfast it was "inevitable" that he would get sick during the challenge.

David Walliams' Big Splash is on 8 March. 9pm on BBC One