Leonardo DiCaprio has opened up about a shark encounter that nearly took his life.

The actor was filming "Blood Diamond" in 2006 when he took a break to go on a shark cage diving expedition in Cape Town, South Africa.

He told Ellen DeGeneres: "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."

An organization dedicated to protecting sharks invited the actor on the expedition, but he won't repeat the experience.

"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," he added.

DiCaprio currently stars in "The Wolf Of Wall Street."