How do you make Emma Watson love a beast?

That was the critical question throughout filming the live-action reboot "Beauty and the Beast," and star Dan Stevens searched the animated version of the movie for inspiration.

"One of the things I really wanted preserve from the animated film was just how funny and sweet and silly the Beast is, as well as being this great hulking scary thing sometimes," Stevens tells Made in Hollywood reporter Kylie Erica Mar.

In the end, he says, "We decided he had to be funny. He had to have a sense of humor. He had to be intelligent and witty. So we translated some of that humor more into a dry wit that he has, which I really enjoy."

https://youtu.be/vzlfmF3LFzQ

Tapping into the nuances of the Beast character proved particularly challenging for Stevens, best known as the star of "Downton Abbey," because of the technical demands of motion-capture technology. What Stevens did -- and wore -- on set looked nothing like it would in the finished movie.

"There was a prosthetic muscle suit but no fur, or anything, and nothing on my face," he explains. "So I was puppeteering a muscle suit on stilts for the physical capture, and then the facial capture was done separately. That's been for me one of the most delightful aspects of seeing the finished movie, of seeing how this sensitivity of the human face can be born through using this technology."

That meant that the iconic ballroom scene, when the Beast waltzes with Watson's Belle, had to be shot a couple of times -- once showing his full body, then a second time focusing only on his facial expressions.

"I waltz with my face. It was quite weird," he says. "That was one of the interesting things about that facial capture process was sitting in this booth and doing everything we've done in all of these scenes, whether it was eating or sleeping or shouting or talking or waltzing. They would spray my face with UV paint and these 27 little cameras would capture it."

So what's his waltz face?

"It depends which bit of the waltz you're looking at, but he had to look lovingly at Belle a lot of the time," says Stevens. "There's a particular feeling that you get when you nail a waltz with somebody. And it's almost an ecstatic feeling of joy. I just had to feel joyful and in love. It's a lovely moment of storytelling through dance, that Belle reminds the Beast that he used to love dancing, and she teaches him the first few steps, and then he gets the hang and pretty soon he's waltzing -- on stilts."