Billie Eilish and Finneas O'Connell Surprise Classroom of First Graders in Their Hometown of L.A. (Exclusive)

Class is in session!

In a clip premiering exclusively with PEOPLE on Wednesday, Dec. 18, Billie Eilish and brother Finneas O’Connell appear on the latest episode of Celebrity Substitute — and teach a class of first graders at Garvanza Elementary School in Los Angeles how to write a hit song.

In the opening of the clip, Eilish, 23, and Finneas, 27, appear before the class and she instructs them to create a loud drum roll — which makes the kids get loud and excited.

In the following scene, the "Birds of a Feather" singer — who also celebrated her birthday on Wednesday — lines them up for a performance of their original song titled "I'm Just a Polar Bear."

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"Wiggle, wiggle," she instructs them to do to shake off the performance nerves, before welcoming their teacher, Mrs. Fowler, back to the classroom.

"We're going to be performing a song they just wrote called 'I'm Just a Polar Bear,'" Eilish says to the teacher. O'Connell, who's seated at the keyboard, adds: "And Julian's going to hold cue cards like we're on Saturday Night Live."

"And this is Friday live... Friday day live," the "Everything I Wanted" singer jokes.

The full episode will air Thursday, Dec. 19 on YouTube.

Celebrity Substitute, hosted by Julian Shapiro-Barnum, is a digital series where celebrities substitute teach their skills to a class of elementary school kids. Previous celebrity substitutes include Cynthia Erivo, Florence Pugh and Andrew Garfield. The show is sponsored by Amazon and each episode fulfills the school's Amazon Wish List to support teachers and students.

In addition to her classroom endeavors, Eilish is currently on the road for her Hit Me Hard and Soft tour, which began in late September.

The tour is in support of her latest studio album, which she released in May, and earned her seven nominations for the 2025 Grammy Awards.

Related: Billie Eilish Compares Her Frequent Social Media Usage to Smoking 'Cigarettes': 'It's Really a Problem'

On Dec. 11, she shared an Instagram Reel of herself and O'Connell working on the early stages of her hit song "Birds of a Feather."

"February 16th 2023 lil video of the beginnings of birds of a feather 😋😋," Eilish captioned the post.

The video showed the duo discussing the lyrics to the chorus, which would eventually become, "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."

"I love that idea," Eilish said as O'Connell discusses how the song should be sung.

Read the original article on People