Chris Hemsworth -- who's known for looking good shirtless -- snapped a selfie on Sunday that revealed just how frail-looking he became for his In the Heart of the Sea role.
"Just tried a new diet/training program called Lost At Sea," he Instagrammed to his 869, 000 followers, "Wouldn't recommend it.. #IntheHeartoftheSea"
Ron Howard's action-adventure movie follows the aftermath of the real-life maritime disaster that inspired Herman Melville's Moby Dick. In the winter of 1820, the New England whaling ship Essex was attacked by a whale, leaving the surviving crew to do the unthinkable to stay alive in the face of storms, starvation, panic and despair.
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Chris Hemsworth reveals dramatic weight loss for 'In the Heart of the Sea' role
LONDON, ENGLAND - APRIL 21: Chris Hemsworth attends the European premiere of 'The Avengers: Age Of Ultron' at Westfield London on April 21, 2015 in London, England. (Photo by Mark Cuthbert/UK Press via Getty Images)
Liam Hemsworth attends a premiere for "The Dressmaker" on day 5 of the Toronto International Film Festival at the Roy Thomson Hall on Monday, Sept. 14, 2015, in Toronto. (Photo by Evan Agostini/Invision/AP)
Actor Hugh Jackman attends the premiere of "Pan" at the Ziegfeld Theatre on Sunday, Oct. 4, 2015, in New York. (Photo by Evan Agostini/Invision/AP)
LOS ANGELES, CA - JUNE 16: Actress Nicole Kidman arrives at Women In Film 2015 Crystal + Lucy Awards at the Hyatt Regency Century Plaza on June 16, 2015 in Los Angeles, California. (Photo by Axelle/Bauer-Griffin/FilmMagic)
** FILE ** In this Monday, Nov. 6, 2006 file picture, actor Heath Ledger arrives for the premiere of his film "Candy" in New York. The NYC medical examiner reports that Ledger died as the result of acute intoxication by the combined effects of oxycodone, hydrocodone, diazepam, temazepam, alprazolam, and doxylamine. (AP Photo/Dima Gavrysh, File)
Cate Blanchett poses for photographers upon arrival at the premiere of the film 'Carol', as part of the London film festival in London, Wednesday, Oct. 14, 2015. (Photo by Grant Pollard/Invision/AP)
Sam Worthington attends the press conference for "Cake" on day 6 of the Toronto International Film Festival at the TIFF Bell Lightbox on Tuesday, Sept. 9, 2014, in Toronto. (Photo by Evan Agostini/Invision/AP)
LOS ANGELES, CA - APRIL 16: Actress Rose Byrne attends the Burberry 'London in Los Angeles' event at Griffith Observatory on April 16, 2015 in Los Angeles, California. (Photo by Axelle/Bauer-Griffin/FilmMagic)
Margot Robbie attends Cantor Charity Day 2015 hosted by Cantor Fitzgerald and BGC Partners on Friday, Sept. 11, 2015, in New York. (Photo by Andy Kropa/Invision/AP)
"We have to shoot the really skinny stuff where we drop down to five, six, 700 calories a day, a good three or four weeks and it's going to be pretty uncomfortable, but we'll be together in our misery," the 32-year-old actor said. "I spend more time thinking about food than anything else at the moment."