chris hemsworth, weight loss, in the heart of the seaChris Hemsworth is all imposing muscle as Thor in the "Avengers" flicks, but for his newest role, as a ship crew member lost at sea in "In the Heart of the Sea," he decided to take his physique in the complete opposite direction.

Hemsworth unveiled his dramatic weight loss in a photo posted on social media this weekend, looking almost unrecognizable with a thick, scraggly beard and long, tangled hair. But it was the visible rib bones and collar bones poking out of his too-skinny torso and chest that caused the most concern, as the actor looked less like the God of Thunder and more like Tom Hanks in "Castaway."

Hemsworth added a cheeky caption to the shot, writing, "Just tried a new diet/training program called 'Lost At Sea'. Wouldn't recommend it."

Earlier this year, Hemsworth revealed just how he achieved such a shocking transformation, telling Entertainment Tonight that he and his fellow castmates consumed as few as 500 calories a day for weeks at a time so they'd look convincing as stranded sailors.

"We have to shoot the really skinny stuff where we drop down to 5, 6, 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," Hemsworth told ET back in July. "I spend more time thinking about food than anything else at the moment."

It looks like mission accomplished. Now will someone go get this man a sandwich?

"In the Heart of the Sea" opens on December 11.

[via: Chris Hemsworth, Entertainment Tonight]

Photo credit: Chris Hemsworth/Twitter