Comedian James Corden has been challenging Olympic diver Tom Daley to a high dive contest.
In a TV sketch made for Sport Relief, Corden shows off his technique to the star diver, in an attempt to prove he's a diving diva.
This year, Sport Relief is taking place from Friday 19 March to Sunday 21 March.
And the Tom Daley sketch is just one of the weekend's highlights,like James Corden training Manchester United.
At the heart of the weekend is the Sport Relief mile, where many thousands of people will run a mile for charity.
Celebrities like David Beckham are urging people to join in, whatever their age.
The 16 main events will be held in Belfast, Birmingham, Brighton, Bristol, Cardiff, Gateshead, Glasgow, Hull, Leeds, London, Manchester, Milton Keynes, Norwich, Nottingham, Plymouth and Southampton, but there are hundreds of other smaller ones too.
James Corden trains Wayne Rooney
Sport Relief star David Walliams has been getting on his bike for Sport Relief and has already battled through temperatures of -15C through the highlands of Scotland as he starts his challenge to cycle the length of the UK.
And in the recording studio Robbie Williams has made a Sport Relief single called Morning Sun.
In another of James Corden's contributions to the charity weekend, he gives Manchester United a training session and takes them through a gruelling regime.
Blue Peter's Helen Skelton has taken six weeks to travel the length of the Amazon River in a kayak!
It's hoped she has broken the Guinness World Record for the longest solo journey by kayak and has become the first woman in history to solo kayak the Amazon.
On completing the challenge, an exhausted but very proud Helen said: "I reckon that you shouldn't shy away from things because they're tough or you might fail.
"Get stuck in and you never know where you might end up."
The first Sport Relief kicked off in 2004, and a second event was held two years later.
So far more than £20m has been raised for good causes.