Unusually short actors have it tough in Hollywood, usually relegated to characters whose size is the entire joke of their existence. Even so, there are names who have risen above to become respected as actors. Two of the most notable examples are Warwick Davis and Deep Roy, but the ultimate example right now is Peter Dinklage, best known for his Emmy winning role as Tyrian Lannister in Game of Thrones. He's now branching out from that, having been cast in X-Men: Days of Future Past.
Nothing is known about the part he is actually playing, but it's a testament to just how beloved the actor has become when the simple news of his casting has been making it's way around the internet with such fanfare. You'd think that Liam Neeson had been cast, though Dinklage certainly belongs aside him in pedigree.
The most widely speculated part for him to play is Puck, a dwarf in the Marvel Universe with super-strength and agility. Whoever he winds up playing, we can be sure that he'll play it well!