Academy Award-nominee Jake Gyllenhaal, 30, isn't one to shy away from a healthy dose of danger, as viewers could see on Monday night's season premiere of the Discovery Channel's Man vs. Wild, on which host Bear Grylls took the unsuspecting movie star to the Icelandic tundra during a blizzard that shut down local airports for days.

Gyllenhaal had to cross a freezing river sans shirt (so as to keep it dry), get lowered into a hole to gut a dead sheep for the duo's meal, and — perhaps most harrowing — cross a 150-ft deep river gorge by slithering on his stomach on a tightrope. The actor, who has a fear of heights, was terrified by the prospect. "This is one of those moments, face your fear," he said. "That is legitimately scary," he added, peering into the ravine. His new friend Grylls was supportive. "What I've learned is that there's never a good time," he said when he saw Gyllenhaal was hesitating. "Just do it."

After the actor had gotten safely across the gorge, he had conquered his fear. "That was a moment I'll never forget in my life. It was incredible," he said after he was safely on the other side. Grylls was also impressed. "You've gotta admire somebody when they step out of their comfort zone and put their life in somebody else's hands," he told the Los Angeles Times. "I was very clear with him and said, 'Come on your own and trust me.' He did incredible. What I like about the wild is when you're squeezed, you see what people are made of."

Watch the nail-biting scene here: