WARNING: The following contains major spoilers for Soul, now streaming on Disney+.

Pixar's latest film, Soul, featured musical contributions from an unlikely source -- a middle jazz school band out of Oakland, California.

Members of the Edna Brewer Middle School Jazz Band played "Things Ain't What They Used to Be" written by Mercer Ellington in the animated film, according to a report from SFGate. The band was recruited to play the song for the film after producer Dana Murray heard them playing while dining at a restaurant in Oakland's Jack London Square.

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"I never really thought I'd get that opportunity," said Kazeem Elebute, a former Edna Brewer jazz band member. Upon arriving at the Pixar studio in Emeryville, he couldn't believe it was "really happening."

Edna Brewer's Middle School Jazz Band "played at Skywalker Sound in Marin County, as Pixar recorded the music and caught close-up video of them playing to use as a guide as they illustrated the musicians in the animation," SFGate reported. The band also revealed that Pixar asked them to play "like beginning middle school music students."

In addition to performing the song, the middle school jazz band, and their music director Zack Pitt-Smith, served as a template for the class of music students featured in the film. The rest of the music featured in the film was composed by Grammy-winning jazz musician Jon Batiste, who contributed several ideas about jazz that made it into the film's plot.

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After spending time with the class, Pixar and Yamaha offered to donate $10,000 to Edna Brewer to buy more instruments. However, Pitt-Smith declined the offer and suggested that the money be given to another school in the district with more needs.

Soul tells the story of Joe Gardner, a middle school band teacher and aspiring jazz musician seeking to reunite his soul and body after they are accidentally separated.

In addition to featuring a solid jazz soundtrack and uplifting message, the family-friendly film also made headlines after its release for including a hilarious explanation for the New York Knicks' losing record. The explanation is given when Joe is introduced to the "Zone" by a spirit named 22, who reveals that she's been messing with the team "for decades." She then hurls an object at one of the team's players, causing them to lose (again).

Directed by Pete Docter and Kemp Powers, Soul stars Jamie Foxx, Tina Fey, Questlove, Phylicia Rashad, Daveed Diggs and Angela Bassett. The film is currently available on Disney+.

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Source: SFGate