He's an actor.
Good actors, which you have said he is, can change who they are by, like, acting.
Here, I think Ian can explain it better than I can:
YouTube - Sir Ian McKellen, On Acting
Just for the sake of being picky and a naysayer:
When they get the shoulder anatomy correct, I will be much happier. Right now all I see is muscle suit under latex and spandex. That shoulder looks so odd.