Leonardo Dicaprio is terrified of sharks after getting trapped in a cage with one.

The 'Wolf of Wall Street' star has revealed a ''gigantic great white'' tried to attack him when a shark cage diving expedition went horribly wrong in Cape Town, South Africa in 2006, while he was on a break from filming 'Blood Diamond'.

The 39-year-old actor recalled the encounter during an interview on 'The Ellen DeGeneres Show' today (07.01.14) and said: ''I had a huge fear of sharks, and when I did 'Blood Diamond' in 2006 I actually got stuck in a cage with a great white, which was awesome.

''It was a gigantic great white ... They actually said in 30 years this has never happened, but the tuna kind of got stuck on the top of the cage and the great white leapt out and tried to bite it and went into the cage with me.

''Half of its body was in and out, and I flattened down at the bottom, and it was this far away, and it chomped a few times but I survived it.''

Leonardo was invited on the expedition by an organisation devoted to protecting sharks but admitted it left him mentally scarred.

He said: ''I don't want to do that anymore, but I don't want to discount their work because they're doing great stuff. But it was absolutely terrifying.''