It's no secret that Billie Eilish became a star at a young age, but it turns out she was involved in the music industry even as a child, long before she went viral with her debut song "Ocean Eyes" at the age of 13.

Eilish was only around 8 or 9 years old when she appeared in the music video for "Hollow" by obscure 2000s L.A. alternative rock band Herd the Humans. The somewhat hard-to-find music video was directed by Hart D. Fisher, who was Eilish's neighbor at the time.

"When Billie was a little girl growing up next door to me in Los Angeles, I always knew she was going to go somewhere, be someone, but when I cast her to act in my American Horrors TV series and in one of my music videos, I had no idea just how high she would go," Fisher revealed to Horror Society in 2020, calling Eilish an "intense presence."

In a behind-the-scenes clip posted to Facebook in 2020, Eilish can be seen working on a kids' activity book with her dad on set. The clip also reveals that Eilish's character in the music video is called "Little Death."

"We had a lot of fun, Billie was a total trooper, her dad Patrick was great (thanks Patrick!), and we are all so happy for her family and their success!" the caption for the behind-the-scenes video reads.

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The "Hollow" music video sees a young Eilish with her signature serious facial expression sitting in a fancy children's dress in the middle of a chaotic house party.

Throughout the video, the baby-faced Eilish watches the adults party around her as they participate in a dance circle and more. At some point in the video, she strokes the hair of a woman who appears to be passed out or dead.

"It was a crazy shoot punctuated by the fact that NONE of the partygoers booked through Craig's List actually showed up. All of the extras in the video are crew, buddies, and roadies. I want to through a special thanks to everyone who stuck around LATE into the evening, hell, even to the cops who showed up for the noise complaint for being so damned cool," Fisher wrote in a post about the video on Vimeo.

Watch a clip from the "Hollow" music video featuring a young Billie Eilish, below:

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