But luckily, Leonardo DiCaprio survived a close encounter with a great white a few years back after getting caught in a cage with one for a few terrifying moments.
"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," the Wolf of Wall Street star, 39, reveals in an appearance Tuesday on The Ellen DeGeneres Show.
"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."
The diving expedition was for a good cause. DiCaprio was a guest of a group devoted to protecting sharks. Looking back, he's happy that he didn't almost die just on a lark.
"I don't want to do that anymore," he says of swimming with sharks, "but I don't want to discount their work because they're doing great stuff. But it was absolutely terrifying."