Robert Downey Jr. made a well-deserved comeback to Hollywood by the time Iron Man launched the MCU, but there was certainly some growing pains. In a clip from his interview on My Next Guests Needs No Introduction With David Letterman, the former MCU star spoke about what it was like working on the 2008 film, which was released before Marvel was owned by Disney. Mainly, he indicated that Iron Man's helmet was a pain in the ass, and it made it very difficult to see.

"Excellent question," he replied when asked if the Iron Man helmet was actually there during those suiting up scenes. "Initially, everything was really there. They wanted to spend as little as they could on CG replacement, 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.' So I put this helmet on, and it slammed closed, and I couldn’t see anything, and then these LED lights went on and it was like The Manchurian Candidate... I was absolutely blinded."

By the end of his tenure in the MCU, Downey Jr. made it clear that he wasn't very happy about the suit. "By the time we were doing the last Avengers, they'd just be like, 'Hey Robert would you mind putting on that helmet? No?! Yes? No, put two dots here and then you can paint it in later," he joked.

Watch the clip from the interview above, and look for the full episode on Oct. 21.