The original 2015 film was set inside the mind of an 11-year-old girl, Riley, with her five main emotions personified as characters.
It was a huge box office hit and won critical acclaim, so it's little surprise that the studio has green-lit a follow-up.
Here's everything we know about Inside Out 2 so far.
Inside Out 2 release date
Inside Out 2 will be released in UK cinemas on 14 June, 2024, nine years after the original film came out. It will be made available to stream on Disney+ at a later date.
The long-awaited movie was officially announced by star Amy Poehler at Disney's D23 expo in September 2022, following years of speculation.
Director Pete Docter first discussed the prospect of a sequel in 2015, telling Entertainment Weekly: "There's no sequel idea from me at this point. Never say never." In early 2016, he said he would "explore" possible ideas for Inside Out 2 and "see what happens".
Fans' hopes were dashed when Pixar announced it would focus on developing original films, rather than sequels, after the release of 2019's Toy Story 4. But the studio changed tack by releasing a Toy Story spin-off, Lightyear, in 2022, paving the way for both Inside Out 2 and Toy Story 5 to enter production.
It was later announced that Kelsey Mann would be directing Inside Out 2.
Inside Out 2 trailer
The first teaser trailer for Inside Out 2 arrived in early November and with it came a brand new emotion.
Just as Joy, Sadness, Disgust, Anger and Fear though they had Riley's feelings under control, her teenage years strike and bring with them a dose of orange-haired anxiety.
Hit play on the teaser above to re-enter Riley's head.
Inside Out 2 plot
The original Inside Out ended with Riley's emotions discovering puberty, so the sequel will pick up where it left off by focusing on Riley's adolescence. Perhaps the most notable change this time around is the addition of a whole new emotion named Anxiety.
"In some ways, Inside Out set itself up for a sequel and we're going there," Poehler told People magazine, adding that the new film will be "deeper" than the original.
She added: "We're going to have what it feels like to be a teenager, the new emotions that live inside a young person's brain.
"In many ways, it was really exciting. We knew exactly where we were. We go to the teen brain and we see the madness that lives inside there.
"A lot has happened since the first film in terms of the emotional intelligence and how we think about mental health and how our emotions can affect us physically, and what's really going on inside our head."
Pixar previously tackled the topics of puberty and teen angst in 2022's Turning Red.
Inside Out 2 cast
Poehler will return to voice Joy in Inside Out 2, while Phyllis Smith and Lewis Black will reprise their roles as Sadness and Anger retrospectively.
Two original cast members, Mindy Kaling and Bill Hader, have been recast. The Equalizer star Liza Lapira has replaced Mindy Kaling as the voice of Disgust, while Arrested Development's Tony Hail will provide the voice of Fear, instead of Bill Hader.
Kaling told The Wrap in January 2023: "I had a great time working on Inside Out and am sure Inside Out 2 will be great, but I'm not working on it."
Stranger Things star Maya Hawke will join the cast as Anxiety. Mann explained: "Anxiety, voiced by Maya Hawke, might be new to the crew, but she’s not really the type to take a back seat. That makes a lot of sense if you think about it in terms of what goes on inside all our minds."
Oscar nominee June Squibb, who previously voiced characters in Soul and Toy Story 4, has been cast in an unknown role.
There's currently no word as to whether Inside Out 2 will feature an appearance from Riley's former imaginary friend Bing Bong.
Inside Out 2 crew
Inside Out 2 will be helmed by first-time director Mann, who previously worked on Pixar films The Good Dinosaur, Monsters University, Lightyear and Onward.
Pete Docter, who directed the original film, will oversee the sequel as executive producer. Docter is now the Chief Creative Officer at Pixar, and he also directed Monsters, Inc., Up and Soul, so his continued involvement is promising news for fans.
He told The Wrap that Mann's pitch for the sequel was "really poignant and very heartfelt, very personal to him but also universal". The film is broader in scope and a "little bit more truthful" than the original, he added, and has "a real great heart to it".
The script will be penned by Meg LeFauve, who co-wrote the first Inside Out with Josh Cooley and Docter. She also worked on The Good Dinosaur and Onward.
Inside Out 2 will be released in cinemas on 14 June 2024.