I was like, ‘You go ahead and get all buff. What are you having to eat? A piece of lemon? OK.’ [Laughs] We really hit it off since the beginning. It was nice that we had some time before the movie shot to really get to know each other. And I’ve known him briefly here and there — just a small world in Los Angeles. I mean, the biggest challenge with him was that sometimes we’d just get on these laughing fits, and it’d be time to shoot, and I’d be like, ‘All I’m really doing right now is trying not to laugh.’ I thought all that went really well, fortunately, toward the parallel we have in the film."
Sebastian Stan, on working with Chris Evans (source)
And I don’t know about anyone else but the mental image of the men playing Steve Rogers and Bucky Barnes having giggle fits is the most precious thing ever.