Oscar-winning composer and award-winning songwriter Finneas is no stranger to writing music for film. The composer and songwriter won Oscars — with his superstar sister Billie Eilish — for “No Time to Die” from the James Bond film of the same name, and “What Was I Made For?” from “Barbie” in 2024. He has won Grammys and has a solo career as well as multiplatinum music with Eilish. He is a songwriter of all trades, but when it came to writing music for AppleTV+’s limited series “Disclaimer,” the series creator and director Alfonso Cuarón wanted something different from him.

Despite Finneas’ extensive resume, he had never scored TV, but Cuarón was a fan. Although the musician was on board during filming, it wasn’t until post-production that the work really began. “He sent me a bunch of music that he loved as references, and it was mostly string quartets,” Finneas says. “I was immediately like, ‘Oh my God, I don’t know how to write music for a string quartet’ so I had to learn.”

The seven-part series stars Cate Blanchett, Kevin Kline, Sacha Baron Cohen and Kodi Smit-McPhee. The show follows acclaimed journalist Catherine Ravenscroft (Blanchett), who built her reputation revealing the misdeeds and transgressions of others. When she receives a novel from an unknown author, she is horrified to realize she is now the main character in a story that exposes her darkest secrets.

Finneas started writing the music and brought on composer David Campbell “to notate and write what I had written and then orchestrate it into parts — because I don’t know how to write sheet music.” It was Campbell who recommended the Attacca Quartet, and since Cuarón was a string quartet buff, he already knew the prestigious group of musicians.

In approaching the score, Finneas notes that most of Cuarón’s films, like “Roma” and “Y Tu Mama Tambien,” “don’t have a score,” so the “less is more” approach seemed appropriate. “There are big montage sequences, like the water rescue, where we knew we needed the momentum of music, and there are moments where the music is a little bit of an inner monologue of character,” he says.

Episode 7 reveals Catherine’s secret. Jonathan, the young man she had met on holiday and rescued her son from drowning, would later return to her room and assault her. Cuarón gave Finneas a piece of music for the scene. He says, “I thought it was super haunting, and it just felt like the right horrible thing to play” under the realization that the narrative that had unfolded and destroyed Catherine’s life was untrue. With that realization, all the fantasy music that had come before had to shift with the narrative.

When it came to instruments, he gave Catherine a cello theme that could be heard early in Episode 1. He also created a family suite. Catherine’s son, Nicholas (Smit-McPhee) “is mostly listening to rap, grime and drill,” and that’s a bit at odds with the rest, “so you hear that with the cello, married with synths that you hear with [husband] Robert (Sacha Baron Cohen).”

Elsewhere, he created different themes including a love theme for Steven (Kevin Kline) and his late wife Nancy (Lesley Manville) who appears in flashbacks.

As for his experience scoring for TV, Finneas says he didn’t work in a linear way. “I would work on cues from Episode 6 and then 2,” and jump around, “which was satisfying.”

He adds, “If I were to do more television, I would hope I’d get to do that again, because, you know, it’s appealing to do it that way.”