Tia Fuller has toured the world in Beyoncé’s band, performed a concert for President Barack Obama at the White House, and appeared on the Today Show, Good Morning America, Oprah, and at the Grammy Awards. But the Berklee professor says that none of that made her as nervous as playing for her latest gig.

Fuller is the saxophonist behind the music of Dorothea Willams, a character in Pixar’s new film, Soul. The character, voiced by the legendary actress Angela Bassett, is a renowned musician who leads a jazz quartet. The film, which also stars Jamie Foxx, Tina Fey, Questlove, Phylicia Rashad, and Daveed Diggs, tells the story of a band teacher who becomes separated from his body, then finds himself in the Great Before, a world where souls get their personalities before coming to Earth.

Soul will be available to stream exclusively on Disney+ starting Friday, December 25. We recently talked to Fuller about her role in the new film. Edited excerpts from the conversion are below.