From a very early point, we knew that John C. Reilly was really the only guy who could play Ralph. It’s because he is so human as an actor. The characters that he plays, to me, feel like real people. There is always a warmth and a humanity to those characters, regardless of how broad they are. Whatever goal they are pursuing, I always find myself rooting for these characters. And that is exactly what I wanted for Ralph.

She was really inspired by Sarah because I’m a huge fan of Sarah Silverman. Sarah wrote a book — it’s basically her autobiography or memoirs — called The Bedwetter. I was so inspired by it. I loved listening to it when I was driving. I loved listening to Sarah read the book and describe her life. Especially her life as a kid growing up and the things she believed. That she was a miniature version of how she is now — naive, but wholly inappropriate. I was just like, that is so great. I could really see a character in that. It would be great to have that represented in an animated film.

I’ve always loved Sarah’s work, and I felt that she was an untapped source. That she was being typecast as a certain character in live-action movies. She would be a great voice for animation, especially for a kid character. Especially taking the bed-wetting analogy. This thing that she was so ashamed of as a kid became this thing that pushed her into comedy — to be able to talk about it, to make jokes about it. It was an angle that Sarah was so familiar with that she really embraced the character 100% right from the beginning.

Working with Sarah in developing the character made the character more profound and made her feel more real, like a three-dimensional character where you really kind of feel for this kid. Being able to play the part having lived it as Sarah did as a little girl just brought so much richness to the performances. So Vanellope was always there. First it was a buddy movie, and then it became this threesome movie, where it was Felix, Ralph, and Vanellope traveling together through the bulk of the film, which was fun.

But then it seemed like the heart of the story is really between a big brother and a little sister. That was really what the movie was about. Ralph maturing from this selfish, almost adolescent type of character into someone who was more mature and put the needs of this kid before his own. So over the course of time, it really became a story about those two. How meeting Vanellope was the best thing for Ralph and it helps him grow.

It was instrumental to have John come in so early in the development process of the character because I knew [he] would bring so much to the character, things that I wouldn’t even think of. Which he absolutely did. John would always say, "I’m the one who is going to be wearing the skin of this guy. I really want to understand him." He is a very internal actor when it comes to that. Even in developing the look of the character, there were moments where I would show John, and say, "What do you think of this?" Even in live action, he has his opinions on costumes and what his characters look like.

The fact that we had the two of them on the stage together recording the dialogue really brought the acting [up]. Being able to look into one another’s eyes when they were recording and acting with each other was a huge benefit to getting moments that felt very genuine.

Unfortunately, in animation, this is something that doesn’t happen a lot. It was very important to me that we did do it this way because I felt I would really get the best of John and Sarah having them in the same room together.

I think that is the magic of, especially of, John’s work. He likes to play against other actors. I felt like [without that] I wouldn’t be getting his best, and I wouldn’t be able to give the audience that chemistry between our two main characters.

I wanted that kind of collaboration between us as we were fleshing out these characters. This is the first time John C. Reilly and Sarah Silverman have been in a movie together, so I felt like I would be short-changing the audience if I did not give them the actual exchange between the two of them.

We had a great group. A great little family working together. Our records would be the actors and myself and Phil Johnston, the screenwriter, and Jennifer Lee, who co-wrote the script with Phil, and my head of story, Jim Reardon.

What we would do is, I would have the actors go through what was on the printed page a few times and we would record that. Then we would have a conversation, all of us, about how the scene could be better. The language of it, the direction of it. The charge. Was the scene coming across as funny, or sad, or emotional — or whatever it needed to be? Were we getting it in the best way possible?

That’s when I would kind of let the actors play around with it, between the two of them. Once they knew what the scene was about, what we were going for, then I was very comfortable with them taking it in other directions.

I would always let the actors take it too far. Because then that way I would be able to reel it back, pull it in at the end. And those were usually the takes where we would really get the gold on those readings. And it was a way that everyone really enjoyed working, because it felt like everyone was bringing their best to the table.