In the late 1990s, Dav Pilkey launched the first children’s novel of the Captain Underpants series—a series which would become tremendously popular among young readers. Despite the series’ acclaim, it has taken 20 years to see a big screen adaptation, largely because it took Pilkey that long to find someone with whom he could trust his beloved property.

If Pilkey were to agree to a film adaptation, he surely couldn’t find a better director for the project than David Soren, who’s had his eyes on Captain Underpants from the very beginning, and understood the tone and the world that Pilkey had created.

Speaking with Deadline, Soren discusses his aesthetic for the film—based in a mixed media approach—and his belief that more animated films should experiment with film language, even within the studio system.

Dreamworks Animation

How did your involvement with Captain Underpants come about?

I’d been a fan of the books for a long time. I actually stumbled into a book store about 20 years ago, when the first book had just hit the shelves, and I remember picking it up, leafing through it and thinking, “Oh my gosh. I wish I came up with this idea myself.” [laughs]

I knew the studio had optioned it and was developing it. I had a development deal after I finished Turbo, and at a certain point, they approached me about doing it, and I didn’t even have to think twice. I was all in. I’ve got kids and read the books to the kids as well, and it was a no-brainer.

Do you have a sense of why it’s taken so long to see a screen adaptation of this series?

I think Dav Pilkey wasn’t ready to let it go for a long time. The way he tells it, he had a lot of stories that he still wanted to tell within the series. A number of studios had approached him over the years, and I just don’t think he’d felt like he found the right fit—the combination of timing and the right studio and right director.

Dreamworks Animation

What visual approach did you take with this film?

Luckily, Dav Pilkey is a writer and illustrator, so we had a wealth of material on the page to go off of. He did such a great job developing those characters and really fleshing them out visually, so it didn’t feel like the job was to reinvent all of it. It was more to adapt it in a way where people just felt like this is the definitive version of these characters brought to life. That was really the goal, to capture the spirit of what he had done.

The other part of it is, Dav Pilkey was amazingly generous with us. He came in probably about a month after I started on the movie, we were showing him a bunch of development artwork, I was walking him through some of the story changes we were making, and he really loved what he was seeing.

I said to him, “Look, I think the secret ingredient of these books…Even though they’re called Captain Underpants, they’re about George and Harold. They’re about these two boys who are best friends and wildly imaginative, and that’s what makes people fall in love with these stories—this friendship.” I could see a weight being lifted off on his shoulders when he realized I got it, and that was what he’d been going for all along.

Dreamworks Animation

At that point, he empowered us to trust our instincts, and he was very clear in saying he’s not a fan of movies that are just word-for-word adaptations. He was like, “What’s the point of seeing that? There’s nothing new being brought to the table.” He wanted to be able to sit in the audience when this thing came out and be surprised and delighted, even though he invested 20 years of his own life developing all of it himself.

What inspired the choice to integrate so many different forms of animation into this film?

The movie is filled with lots of unconventional mixed media. Really, it’s all designed to feel like it’s the boys’ imaginations being brought to life in different ways and styles. To me, one of the biggest aspects that has made those books so successful and made kids love to read them so much is that every page is a surprise, and he fills them with these unconventional little bells and whistles—these comic books that George and Harold have drawn, the fliperamas that he interrupts an action sequence with to just do a basic flip book treatment to get through it.

There’s lots of unexpected twists and turns in the narrative that he did that keep kids delighted, and that was something that I really felt was necessary in the movie. Obviously, some of those things don’t translate to a visual medium, so we had to find other ways of doing that.

Dreamworks Animation

It actually started with the sock puppet sequence. We were starting to storyboard that sequence, and as written on the page, it was this kind of apocalyptic vision of George and Harold’s future, after they’d been separated and the years start to wear down their friendship. They drift apart and run into each other in the mall and don’t recognize each other, but it was all treated as if it was the CG mode that we were in normally.

I was working with the storyboard artist, and I said, “Let’s just think about this for a second. Is there a way we can make this feel like it’s a bit more in George and Harold’s point of view? They’re in their tree house. The weather’s probably horrible out. They’ve taken their shoes and socks off. Maybe one of them put the sock on his hand, and suddenly we go into their version of this scene, but as told by sock puppets.” The storyboard artist looked at me like, “Can we do that?” I was like, “Let’s try it out and do it till somebody says no.” Sure enough, it was one of the things everybody, including the executives, loved the most at our first screening. That really opened the door for more and more of that, and then the goal kind of became: Let’s make sure that this is really woven through the whole story and not just a little one-off moment here or there.

Dreamworks Animation

Was a sort of meta self-awareness part of the fundamental conceit?

Part of that is there’s a bit of that kind of tone in the books, but it was also another way for us to be unconventional in our storytelling. Nick Stoller, who wrote a lot of the early drafts, was putting a ton of that stuff in there, and I think it just started to help define the tone of the movie. It’s funny that a lot of animated movies don’t mess with narrative style very much. It’s typically pretty conventional. As a result, a lot of kids don’t even know that kind of film language that adults have become accustomed to. It was exciting to be able to do all these weird, unexpected things in an animated movie.

How were the film’s musical sequences developed?

There’s one where the boys have forgotten they actually have to be at school on Saturday for an invention convention, and they wake up in the morning and start singing the “Saturday” song. That actually came about with an improv from Kevin Hart and Thomas Middleditch. We sort of gave them the idea, and they made the song on the fly on their own, kind of fumbling their way through it.

I think both would readily admit they’re not good singers. In fact, Kevin Hart said he would prefer to do nudity than sing. [laughs] They ended up doing that, and it was really funny, and then we created an instrumental track to support it.

Dreamworks Animation

Then, there was the fart symphony later in the movie, when they hypnotize the principal and get him to do their bidding. That was just a sound design dream—or nightmare, depending on who you ask. But it was super fun, and our sound designer went and bought about a dozen different sized Whoopee Cushions, just being a kid again.

Then, we had Weird Al at the end of the movie, which was a huge one. When I was prepping for the movie early on, I was going through all the books, and in the very first book, one of the pranks that the boys pull is they take over the intercom system and play six hours straight of Weird Al Yankovic music. I highlighted it, and I’m like, “We have to get Weird Al.” This was the first month I was on the movie. For almost two years, I was trying to remind people, “This would be a good idea. We should do this,” and then finally, we got to designing our end credits, and the proper time to revisit the idea came up. We approached Weird Al, and he actually knew about his cameo in the books, so he was pretty psyched to do it.

What is it like working with comedians on animated films, which tend to be fairly meticulously scripted?

I’ve worked with a number of comedians over the years, but this cast in particular, they were just so good at improvising and finding the voices of their characters through improvisation that I realized I’d be a fool not to take advantage of that. The sessions really became me and the actor in the booth together. I’m reading against them, and I’ll explain what the parameters of the scene are, what we’re trying to accomplish. We’ll do a version of what’s scripted, then really let them go to town and find their own way to get through it, and do as many ad libs as we can.

Dreamworks Animation

Obviously, there’s a lot of scripted stuff, but a ton of the movie is made up of their ad libs and improvisations, more than any other movie that we’ve done at Dreamworks, for sure. Like you say, most animated movies are so meticulously mapped out and locked down that that kind of spontaneity is gold. Even over the months that come after those improvisations have happened, you still feel the freshness of that idea, and the looseness of it. To have that woven throughout the movie was really instrumental in creating the tone of this thing.

The other part of it was that usually, you show the actors the movie when it’s pretty much done. You can’t change it, and you try to get their buy-offs so that they can go and talk to the press and promote the movie. In this case, because these guys were so instrumental in helping define their characters, we brought them into a very early screening of the movie, still all in storyboard, very much uncooked and not completely solid yet.

It was terrifying because on the one hand, I wanted their advice; on the other, I really didn’t want them to leave the project because they’re like, “This movie’s terrible.” But we did it. They really rolled up their sleeves and pitched in ideas and helped solve some of the bigger issues that we were dealing with at the time. Then, in subsequent recording sessions, they’d always come in and ask, “All right, so what’s changed? How are you solving some of this stuff? How can we help?” It was amazing. They really became creative partners on the movie, instead of just doing their parts.