Robert Downey Jr. revealed in an interview with David Letterman that his original Iron Man helmet was so uncomfortable to wear while acting that he refused to wear it while filming later Marvel Cinematic Universe projects.

"Initially, everything was really there," Downey told Letterman in a recently released clip from Netflix's My Next Guest Needs No Introduction with David Letterman.

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"They wanted to spend as little as they could on CG replacement," he said. "So I remember this helmet went on, and there'd be a shot, and I'd be in this whole suit, and they'd say: 'All right, Robert, it’s like you landed on the roof, so when we say action, just go like that, like you just landed, and then start moving forward... Then these LED lights went on," Downey continued. "And it was like Manchurian Candidate... I was absolutely blinded."

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Downey confirmed that when he was filming the last Avengers film, he abandoned the real helmet, noting, "They’d just be like, 'Hey, Robert, would you mind putting on -- 'Helmet?! No! Yes, no. Put two dots [on my face], and then you can paint it in later.'"

The new season of My Next Guest Needs No Introduction features in-depth conversations with Downey, Kim Kardashian West, Dave Chappelle and Lizzo. All four episodes will be available on Netflix, starting Oct. 21.

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Source: YouTube