The 2008 gold medallist recorded the video during a training break at the Olympic Village in London and uploaded the clip to his YouTube account.
Mitcham said: "Someone on twitter asked me to upload a video of me playing the ukulele. I profess to be neither a great instrumentalist nor singer.
"I'm just an Olympic diver who likes to strum away in his spare time."
© PA Images / Alastair Grant/AP
The Australian will compete in the men's 10m platform diving event on Friday, August 10.
He is the defending champion after performing the highest-scoring single dive in Olympic history at the Beijing Olympics back in 2008.
Photo gallery - London 2012 Olympics:
Copyright: Martin Rickett/PA Wire/Press Association Images
