In an interview with Cinema Blend, actor James McAvoy reveals that Professor X will not go bald in X-Men: First Class and that this fact helped him settle into the role easier. According to the article, the character was to go bald during the film but was then vetoed out by the studio.
On being free from the constraints of the previous films:
McAvoy revealed that Xavier was initially going to be bald, but the studio vetoed the idea. Apparently this detail alone was enough to help him escape from under the weight of Stewart's performance and left him saying, "Well f*** it, I’m liberated then."
On his take on the character:
You look at the kind of main, defining characteristics of Professor X, of Charlie Boy, and you go, 'Alright, he’s selfless. He’s a saint. He’s sexless, it seems. He’s egoless. He’s all about other people. He’s all about bettering the world and mutantkind and humankind.' And so you kind of try and flip that on its head. You don’t make him an evil person, or anything like that, but you make him ego-driven, women-chasing, he likes a good drink. He’s not the reluctant leader that you kind of want all heroes to be. He actually kind of wants to be in charge, you know what I mean? And all of those things, just to kind of show a journey. So by the end of the movie he’s some way towards becoming Patrick Stewart[‘s version of the character], rather than just having the same guy at the beginning.
And on the reshoots revealed earlier in the week:
We doing a tiny little tweak on the very end, finale thing between me and Michael [Fassbender], who plays Magneto. And we’re doing, what else are we doing? It’s all little bits and bobs and things that we dropped or didn’t know we needed or trying to fix a little scene here or there or tighten up a scene here or there. We’re doing a little bit on a boat at one point, which is going to be fun; then a lot of underwater stuff last week, which I can’t really tell you what it’s about, but it’s quite exciting. Just bits and bobs really.
X-Men: First Class comes out 3 June 2011.