It's hard to imagine anyone other than "The Office" alum John Krasinski wanted the role and got as far as a screen test. "In my head, I got the part," he told Conan O'Brien.

What went wrong? Well, maybe more than one thing, but it sounds like some body insecurity got in the way, thanks to an ill-timed appearance from the impossibly fit Chris Hemsworth as Thor.

Krasinski told his Cap screen test story on "Conan":

"It was a big deal for me. First of all, I love those Marvel movies. I love superheroes. I love imagination. So when they asked me to test, they actually allowed me to put on the suit. I was on a set. It was actually very interesting. ... But I remember the only bummer of it was, I was putting on the suit, just watching, like, 'This is so amazing' and I got about right to my waist. I was still shirtless, feeling pretty good about myself ... and all of a sudden Chris Hemsworth walked by as Thor. And he's like, 'Hey, mate.' And I went, 'I'm good! This is stupid. It's OK. I'm not Captain America. It's fine.'"

Awww. Poor Jim felt body-shamed by the ultimate muscle man. There has to be a lot of pressure for these superhero guys to get and stay ridiculously fit -- from the Chrises to Henry Cavill as Superman, and Hugh Jackman as Wolverine. Krasinski could have gotten himself there, if that's what Marvel wanted, but the bigger question is, would his Steve Rogers have had the right chemistry with Bucky Barnes? That's what the franchise really hinges on.

Watch him tell the story in the video below. The Marvel sniper quip was pretty funny:Want more stuff like this? Like us on Facebook.