The Brilliance of Sibling Songwriting Duo Billie Eilish and Finneas

Billie Eilish and her brother Finneas O’Connell have an unbreakable bond not only by blood but through music. Growing up in Los Angeles, music was the foundation of their upbringing, as both their parents were actors and musicians.

“My whole family is really musical. My brother and my mom both write songs and my dad has always played the piano and ukulele,” Eilish described to Teen Vogue. “When I was 11 or 12, I started writing songs because it’s a good way to express your feelings. My brother is a really good songwriter so we’d give each other notes and write stuff together.”

Both siblings joined the Los Angeles Children’s Choir when they were eight. In addition to writing songs, Eilish is also a dancer, having taken lessons since childhood. Five years older than his sister, O’Connell started writing songs around the age of 11. Wanting to follow in her brother’s footsteps, Eilish also picked up the writing pen when she was 11, writing her first song about a zombie apocalypse after watching an episode of The Walking Dead.

“But my brother also started writing at the same age I did. I feel like I wanted to write songs just because my brother did, and also my mom did,” Eilish explained to Harper’s Bazaar. “She taught both of us how to write and so I always have high standards for writing. If I didn’t, I’d have 2,000 songs.”

[RELATED: Top 10 Billie Eilish Songs]

O’Connell has been an integral part of developing Eilish’s distinct dreamy voice with eerie, alt-pop instrumentation. In addition to co-writing Eilish’s material, O’Connell acts as her producer, the two co-writing nearly all of her major hits like “Bad Guy,” “Bury a Friend,” “Everything I Wanted,””Happier Than Ever” and “What Was I Made For?” among others, with O’Connell producing the tracks.

He’s also the sole writer and producer of his sister’s breakthrough hit, “Ocean Eyes.” He originally wrote it for his band The Slightlys, but adapted the song to fit his sister’s voice when her dance teacher tasked her with coming up with an original song to dance to. “Ocean Eyes” was the lead single off her debut EP, Don’t Smile at Me, and was her first to chart on the Billboard Hot 100.

“Being able to hear an artist and emulate them has been a huge part of being successful as a producer and co-writer,” O’Connell told Billboard. “I think it’s a problem when a producer comes in to work with an artist, and you can’t hear the artist as well anymore. It’s very important to me to be invisible.”

“We always work together. He’s my partner in crime,” Eilish told Vogue about the working relationship with her brother. “Any sessions that we have, we go together.”

The two have proven to create a winning formula. At the 2020 Grammy Awards, Eilish won the coveted Album of the Year for her debut, When We All Fall Asleep, Where Do We Go?, which was produced by O’Connell. It also won Best Pop Vocal Album, while “Bad Guy” was named Record of the Year and Song of the Year. Eilish was also named Best New Artist.

Photo by Mike Coppola/Getty Images