When Pharrell Williams and Morgan Neville decided to embark on a movie about Williams’ life but animated in Lego pieces, they knew there would be culture shocks. But making “Piece by Piece” still led to some places that neither Williams, Neville nor Lego could foresee.

“We did have extensive conversations about how wide a back of a bikini bottom would be on a minifig in a ‘Rump Shaker’ video,” says Neville, chuckling. “We had many discussions about things I thought I would never be talking about as a filmmaker.”

“Piece by Piece” did not come with any easy-to- assemble instructions. It’s part music biopic, part documentary, part family film. It is, like many things about Williams’ hit-making life, radiant with uplift, beats and idiosyncrasy.

“Society likes to put us in boxes, pun intended,” Williams says, speaking alongside Neville. “Here was a moment where this guy’s view of my life and the way he saw it strung together was incredibly liberating for me. While I’ve never seen myself in a box, this helps other people now to, as well.”

“Piece by Piece,” in theaters now, begins, like many documentaries, with the director, Neville, sitting down with a camera crew focused on their subject, Williams. But in this case, Williams — and everything else, including a bearded, bespectacled Neville — are Lego.

“What if we told my life with Legos?” Williams asks in the film. “That’ll never happen,” replies Neville.

What follows is something like a traditional documentary complete with colorful recounting of past struggles and triumphs, from his upbringing in Virginia Beach to his string of chart- topping hits, told through Williams’ voiceover and a number of talking heads.

It was recorded that way in interviews, either on camera, Zoom or phone, and then animated into Lego form. Here, finally, is a chance to see Busta Rhymes as a Lego, along with many others, including Jay-Z, Snoop Dogg and Missy Elliott.

“The first meeting we had was with Lego because if they had said no, there would have been no film,” says Neville, the director of documentaries including “20 Feet From Stardom,” “Won’t You Be My Neighbor” and “Steve!”

“To their credit, they not only said yes, but I think understood the kind of growth it would force them into,” Neville says.

For Lego, making “Piece by Piece” was its biggest gamble since stepping into feature films with 2014’s “The Lego Movie.” Neville approached the company’s head of global entertainment, Jill Wilfert, with a pitch for what would be Lego’s first foray into a documentary not about itself. Wilfert was immediately responsive.

“The whole idea behind Lego is its endless creativity and limitless possibility, and Pharrell really kind of embodies that,” she says.

As proof of concept, Neville put together a 90- second video of Williams reflecting on his upbringing and the inspiration of artists like Stevie Wonder. (A vinyl of “Songs in the Key of Life” is another one of those things you never expected to see as a Lego.)

“I came away from that saying, ‘This is totally going to work,’ ” Neville says. “And everybody we showed it to got it. They were like: I want to see this movie.”

Still, Neville and Williams knew the Lego approach would mean working within PG parameters. Some things about Williams’ life — like being young and famous while operating in the upper echelons of pop and hip- hop — wouldn’t fit in a family-friendly movie. Williams says the movie “paraphrases” his life.

“There were definitely some areas that weren’t within my expectations of where we might go,” Wilfert says. “We had a lot of good dialogue throughout the whole process. Morgan and Pharrell, there was mutual respect because we are a brand that people have high expectations of and expect certain things of. So we did work with them on areas that we felt did make sense and didn’t make sense.”

It also pushed Lego in other ways. Williams is particularly proud that the movie led to Lego expanding its available skin tones and hair textures. Williams’ Lego self — which he carried proudly to the Toronto International Film Festival premiere of “Piece by Piece” — was specifically designed to match his own skin tone.

“You name the type of human being, we fought hard for their existence and acknowledgment,” says Williams. “Lego obliged, and I think the brand is better because of it.”

One of the movie’s most clever designs is illustrating tracks that Williams crafts himself or in collaboration, like Snoop Dogg’s “Drop It Like It’s Hot,” Gwen Stefani’s “Hollaback Girl,” Nelly’s “Hot in Herre” or Pharrell’s own “Happy.” Each is rendered as a unique little glowing set of Legos pieced together.

Williams, who is Men’s Creative Director for Louis Vuitton, is talented when it comes to brand management. He released his debut solo album, “In My Mind,” in 2006 and long ago stepped into the spotlight, himself. But he has, by his own acknowledgment, remained a producer at heart. Not everything about “Piece by Piece” was easy for him.

“A lot of that was vulnerable for me,” Williams says. “I’m, like, crying two times in the story. I hadn’t considered he might ask questions that would trigger emotion. I’m such a produced person. I’ve produced myself so much.”

It’s a sentiment that Neville, as a protean documentarian used to adapting to the style and attitude of his subjects, can relate to.

“Pharrell as a producer is often holding up a mirror to artists to get them to see themselves. My job is to hold up a mirror to him to get him to see himself,” Neville says. “I feel like, in an odd way, we have the same job.”

When Neville interviewed other musicians for the film, he told them that they’d be animated. But he didn’t say how. It was only later they found out they’d be Lego minifigs.

“Everyone was so shocked and so elated,” says Williams. “I feel like it released the inner child in all of them. Some of them look at life that way, anyways. Other ones, even the tough guys, were like, ‘Oh, man, this is so cool.’ ”

Capturing Williams’ life in a playful, even childlike way will surely help some younger viewers connect to his story. Becoming a world- famous multihyphenate might seem out of reach to most, but “Piece by Piece” makes it look, almost, like a snap.

“There’s a universality that Lego brings out,” Neville says. “I feel like this whole film is an experiment in the tension between the specificity of real life and documentary and the imagination and universality of imagination.”