Blake Lively stopped by 'The Tonight Show' (Weeknights, 11:35PM ET on NBC) to promote her new movie, 'The Green Lantern,' and she revealed an unexpectedly adventurous side to her personality.

On vacation, someone suggested she give swimming with sharks a go. Lively's initial reaction? "I'm terrified of sharks. Sounds like a horrible idea. Let's do it! ... So, I went cage-diving with Great White Sharks!"

From what Lively said, it's a pretty gruesome experience. The guides attract sharks to the cage by throwing blood and fish guts into the water. The divers jump in and start to swim in the cage amidst all that gore. And then lots of sharks turn up and start biting at the cage.

"It's like everything you never wanted to happen, is happening." Happily for Lively, though, she can see the positive side, and thinks that although the experience was terrifying at first, it's also kind of beautiful.