Leonardo DiCaprio is deathly afraid of sharks, so he decided to swim with one -- which didn't go too well for him.

As he told Ellen DeGeneres of his harrowing adventure, way back in 2006 while filming 'Blood Diamond' he was trapped in a cage with a great white shark.

You know, both the biggest and scariest looking one (if you ignore the existence of the goblin shark).

"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 it went into the cage with me," DiCaprio recalled.

"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."

"I don't want to do that anymore," he admitted to the talk show host. "It was absolutely terrifying.

Now that's how 'Titanic' should have ended.