In a recent guest appearance on Jimmy Kimmel Live!, Chris Hemsworth revealed that he nearly died while trekking in the Himalayas with his wife, Elsa Pataky.

The Thor: Ragnarok star shared that his wife was invited by Spanish TV host Jesus Calleja to take on the Himalayas as part of a travel show, and he was her “plus one.” During their ascent, the team went higher and higher until they reached 4,000 metres above sea level.

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“You acclimate every couple of days. You plant yourself in one place and your body adjusts to that lack of oxygen and so on, and you go higher and higher,” Chris Hemsworth recounted in Jimmy Kimmel Live!, as quoted by People. Like a scene in a movie, the 33-year-old Australia native grew “irrational” and “overly sensitive” even to the most trivial of things as the group trekked higher.

One night, Hemsworth felt uneasy and was constantly tossing and turning. According to Us Weekly, when his wife asked what was wrong, he irritably said, “I’m fine, I’m fine, I’m fine!’” He narrated that his breathing was getting worse at the time and was starting sound like “Darth Vader meets Daffy Duck.”

Realising that her husband was in grave danger, Pataky notified the guides who then injected Hemsworth with “all sorts of whatever’s going to adjust” his oxygen. He was later taken down the mountain on an eight-hour drive.

My local Himalayan guide directing me to the top, 3700m above sea level !!

A post shared by Chris Hemsworth (@chrishemsworth) on

The condition is known as altitude depression or altitude sickness, a result of the lack of oxygen in the body. Had Hemsworth stayed in the mountains longer, his brain would not have enough oxygen to function and he “wouldn’t be sitting” with Jimmy Kimmel to discuss the story.

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Despite his fit and healthy physique (he’s Thor, after all), Chris Hemsworth admitted that he couldn’t handle the climb for some reason.

Meanwhile, Chris Hemsworth currently stars in The Huntsman: Winter’s War, now out in theatres.