In a new magazine interview, X-Men: First Class star James McAvoy discussed what he knows and how he feels about the upcoming sequel, X-Men: Days of Future Past, in which he'll star alongside Sir Patrick Stewart, who played Charles Xavier in the original X-Men trilogy. Besides telling the magazine that he hopes to see Sentinels in the film (though he doesn't know or won't say whether they're in the script), he also discussed the problem of Professor X's hair. ...Wait, what? "Simon Kinberg [one of the film's writers] and I had a chat about it and we came up with a whole bunch of idea about how, why and where he might go bald. It's got to be linked to the plot though. In the comics, he lost his hair as soon as his powers awakened, and we clearly didn't follow the source material. It can't just be that he looks in the mirror at the end of the film and goes 'Oh f--k, I'm losing my hair'." He added that he thought the difference in tone for X-Men: First Class was part of the film's appeal, saying that the sense of humor the movie had was a nice addition to the movie canon.. "I thought the biggest thing that X-Men: First Class gave the franchise was a real palpable sense of humor that wasn't just for a couple of moments," McAvoy told Total Film. "It was running through the thing. And I hope that continues. I don't know how easy it will be for me to be a part of that as my character's going to be in a pretty f---ed up place. It's a shame because I like the fact that Charles Xavier was witty and funny and a bit of a lecherous old guy trapped in a 30-year-old's body." X-Men: Days of Future Past will be in theaters July 18, 2014.