“Paddle Boarding With Great Whites,” he captioned the video, adding: “When fear becomes your friend and @themalibuartist captures the moment.”
The video prompted astonished responses from other celebrities, with rapper 2 Chainz commenting: “Helllll naw.”
The actor’s fiancée Katy Perry joked: “Next time go out and put some peanut butter on babe.”
“You’re WILD,” one fan wrote.
Many of Bloom’s followers praised the actor for showing that the sharks, whose numbers have been decreasing in recent years, don’t have to be feared.
“One of the most beautiful and misunderstood fish of the ocean,” one commenter wrote.
“Thank you for co- existing with sharks,” another comment read. “Don’t eat shark fin soup. There should be a ban on finning sharks. Humans kill millions of shark a year to use them in soup, dogfood and cosmetics. It must end.”