Trolls centers on the ever-positive Princess Poppy (Anna Kendrick) who teams up with reluctant hypochondriac Branch (Justin Timberlake) to save their friends from the evil Bergen, who eat Trolls for their happiness.
"By the time we went to pitch to Justin, we had songs from the '70s, '80s and '90s." Mitchell remembers when he first presented the story and the music to the *NSYNC alum: "He goes, 'I know exactly what you are trying to do and I can help you do it even better than you are doing it already.'"
Timberlake signed on to star, and also volunteered to produce the music for the movie. Mitchell says, "It took me all of one second to go, 'Yes! Please! Thank you!'"
The Trolls cast is stacked with musical talent, from pop stars like Gwen Stefani to theater vets Christine Baranski and James Corden. But Mitchell's favorite musical moment is when Kendrick's Poppy belts out a rendition of "September," which they got to record with the actual members of Earth, Wind and Fire.
Timberlake even offered to write an original song, "Can't Stop the Feeling!," for the third act of the movie that was meant to to close out the entire story. Mitchell remembers: "He goes, 'I'll make sure it's a hit song as well.' And I laughed because I thought it was funny, and lo and behold, it is a hit song."
"Feeling" debuted at No. 1 on the Billboard Hot 100 chart, and a music video for the song has more than 263 million views on YouTube. Mitchell added: "Apparently that is just what he does."
Trolls hits theaters Nov. 4.
This article was originally published by The Hollywood Reporter.