Credit: Jonathan Prime

Avengers actor Chris Hemsworth says he lost around 15 pounds in the course of shooting director Ron Howard‘s historical seafaring epic In the Heart of the Sea(out Dec. 11). That may not seem like a huge amount when compared to say the 60-or-so pounds Christian Bale famously made disappear for 2004’s The Machinist. But Hemsworth had already trimmed down to star in Michael Mann’s thriller Black Hat, which he shot immediately before Howard’s movie.

“When I started, I was leaner than my Thor weight, anyway, because I’d been on Michael’s film,” the Australian tells EW. “When you’re already starting off lean, it’s brutal to chew through that kind of weight. Every pound feels like a kilogram.”

In the based-on-real events film, Hemsworth plays a 19th-century seaman called Owen Chase, first mate of whaling ship the Essex, whose captain, George Pollard, Jr., is portrayed by Benjamin Walker. After a whale destroys their ship, Pollard, Chase and the rest of the crew — including characters played by Cillian Murphy and newly minted Spider-Man franchise star Tom Holland — have to survive the elements, and lack of food, in tiny, lifeboat-sized craft.

To convincingly depict starving men, the cast members’ diets were steadily reduced over the course of the production. By the time Howard & co. decamped from London’s Leavesden studios to shoot on the open sea around the Canary Islands the actors were consuming just 500 calories a day.

“We kind of went insane, weighing ourselves every day,” says Hemsworth. “We all felt like a bunch of supermodels, trying to get down in weight for a show, or something. That’s all we spoke about. You’ve got 15 burly blokes on the sea and all we talked about was our diet, and who’d lost more weight, and who’s looking really skinny. It’s ridiculous!”

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In the Heart of the Sea
2015 movie
  • Movie
  • PG-13
  • 121 minutes
  • Ron Howard