The 51-year-old musician announced earlier this year that he would be making the unconventional film about his journey to become one of the most successful record producers alive, having created huge international hits like "Happy", Robin Thicke's "Blurred Lines" and Kelis's "Milkshake."
Since the success of The Lego Movie in 2014, the toy company have also released spin-offs The Lego Batman Movie in 2017 and The Lego Ninjago Movie the same year.
Speaking in Hollywood prior to a preview screening of Piece by Piece, Williams thanked Lego's head of global entertainment Jill Wilfert for agreeing to his idea to animate a documentary about his life in the distinctive style of the building blocks.
"I don't want to make it all heavy, but she said yes to a Black man's story, from a marginalized community," said Williams. "When I was young, that's my origin story."
After the screening, Williams elaborated: "Lego could have said no. I'm Black, in case you hadn't figured that out. But they said yes. I'm not Batman. This is not Harry Potter intellectual property. It's just me, from Virginia. But they said yes."
In the film, Williams is joined by a host of the artists he's collaborated with over the years, including Snoog Dogg, Gwen Stefani and Busta Rhymes.
Piece by Piece is directed by Morgan Neville, best known for his 2013 film about backing singers 20 Feet from Stardom which won the Academy Award for Best Documentary Feature and the Grammy for Best Music Film.
A press release announcing the film said: "Uninterested in making a traditional film about his life, Pharrell set out to tell his story in a way that would set audience's imaginations free.
"Developed from his singular vision, Piece by Piece defies genres and expectations to transport audiences into a Lego world where anything is possible."
In a statement, Williams added: "When I had this crazy vision to tell this story through Lego bricks, I couldn't have imagined a better partner than Morgan. He is a legend. Grateful that Focus wanted to collaborate with us and I'm honored to share this with the world and bring people into my universe.
"Building with Lego bricks encourages us to follow our imagination... who would've thought that playing with these toys as a kid would evolve into a movie about my life. It's proof that anyone else can do it too."
Neville said: "Five years ago, Pharrell Williams approached me with the idea of helping him tell his story through Lego animation. It was one of those rare moments where I knew in a second that this was a journey I wanted to go on."
Piece by Piece is set to be released in the US on October 11, and in the UK on November 8.
Williams is not the only artist to be inspired by Lego. In 2021, Ai Weiwei told The Independent: "I think Lego is no different from Rembrandt's paint or Van Gogh's paint. If they were alive today, they would love to play Legos."