In a captivating clip that premiered exclusively with PEOPLE on Wednesday, December 18th, Billie Eilish and her brother Finneas O’Connell made a remarkable appearance on the latest episode of Celebrity Substitute. This digital series, hosted by Julian Shapiro-Barnum, allows celebrities to share their skills with a class of elementary school kids. At Garvanza Elementary School in Los Angeles, Eilish and Finneas took on the task of teaching first graders the art of writing a hit song.

An Unforgettable Classroom Experience

The opening scene of the clip was truly exciting. Eilish, at 23 years old, and Finneas, 27, walked into the classroom and instructed the kids to create a loud drum roll. The energy in the room instantly became loud and filled with excitement as the young students got into the spirit. In the following scene, the "Birds of a Feather" singer lined up the kids for a performance of their original song titled "I’m Just a Polar Bear." To help them shake off any performance nerves, Eilish told them to "wiggle, wiggle." After the performance, they welcomed their teacher, Mrs. Fowler, back to the classroom. Eilish then introduced the song to the teacher, saying, "We’re going to be performing a song they just wrote called ‘I’m Just a Polar Bear.'" Finneas, seated at the keyboard, added, "And Julian’s going to hold cue cards like we’re on Saturday Night Live." Eilish even joked with, "And this is Friday live… Friday day live."

About the Celebrity Substitute Series

Celebrity Substitute is a unique digital series where celebrities step into the shoes of teachers and pass on their talents to elementary school kids. Previous celebrity substitutes have included Cynthia Erivo, Florence Pugh, and Andrew Garfield. The show is sponsored by Amazon, and each episode fulfills the school’s Amazon Wish List, showing support for teachers and students. This initiative not only provides an educational experience for the kids but also gives back to the school community.

Billie Eilish's Tour and Studio Album

In addition to her classroom endeavors, Billie Eilish is currently on the road for her Hit Me Hard and Soft tour, which began in late September. This tour is in support of her latest studio album, which she released in May. The album earned her seven nominations for the 2025 Grammy Awards, highlighting her significant musical achievements. Eilish's talent and hard work continue to shine both on and off the stage.

Early Stages of a Hit Song

On December 11th, Eilish shared an Instagram Reel of herself and Finneas working on the early stages of her hit song "Birds of a Feather." In the video, the duo can be seen discussing the lyrics to the chorus. The lyrics eventually became, "Birds of a feather, we should stick together, I know (‘Til the day that I die) / I said I’d never think I wasn’t better alone (‘Til the light leaves my eyes) / Can’t change the weather, might not be forever (‘Til the day that I die) But if it’s forever, it’s even better." Eilish expressed her love for the idea as Finneas discussed how the song should be sung. This behind-the-scenes look gives fans a glimpse into the creative process of a hit song.