When I was a kid, my favorite superhero was the Beast. He furry and cuddly. He was built like a football player who could nonetheless jump around like an ape and hang on the ceiling. Most importantly, he was a brilliant scientist who had an expansive speaking vocabulary that he was quite fond of using. My favorite moment was when he told someone to go orally extract the embryonic fluid from a hen's egg. It was almost as good as when Namor the Submariner told Hercules, "May your beard grow inward!"
It's a little suprising (given his physical form) who they've cast for him in the third X-Men film, but it's pretty clear why. They wanted someone who could perform as Hank McCoy the intelligent scientist, and I assume they're figuring they can work out the physical look with special effects, depending on how much they want to spend on Beast's look. If that's their criterion, then their choice is absolutely perfect -- none other than Kelsey Grammer. According to the Wikipedia entry I linked above, he will be the blue and furry second mutation version, but that seems to trace back to this story, which doesn't quote anyone from Marvel as saying that he will be blue and furry. It seems to be more of an editorial assumption, as far as I can tell. You never know how reliable reports from people claiming to have seen something on set are, but this one describes the prosthesis for Beast's head. It doesn't say much, but it does describe blue skin on his neck, ears, and the sides of his head, with black fur on his face. That suggests that it's not the original human-looking but superhuman form.