If life were as poetic as they would like it to be, McAvoy and Fassbender would have bonded while making Band of Brothers back in 2000, playing fresh-faced G.I.'s in the Tom Hanks–Steven Spielberg HBO series, but they didn't shoot any scenes together. Instead, their bromance blossomed a decade later, in the walk-up to 2011's X-Men: First Class, by which time they had developed lengthy résumés and mutual respect. "Before Michael and I even met, I was already willing to go with him and be open to him, because I was like, 'This guy's fuckin' brilliant,'" McAvoy says. "Not to be too fuckin' up your ass or anything like that, but the thing that elevated First Class for me was working with you.