Composer Hildur Guðnadóttir can communicate better through music than through words. So, naturally, it's through instruments that she finds her way into a character's head, most recently Joker's Arthur Fleck. Hildur wrote the initial score for the 11-time Oscar-nominated film after reading only the script. It's rare, she said, noting that the composer usually comes on later in the filmmaking process. But it made all the difference.

"It’s a great place to connect to a story, to find free expression," she says. "As you read, you're making up the tempo and the movements and the pacing of the whole scenario. I had this very strong physical reaction to the story as I read. When I found the first notes of the Joker theme, something completely clicked. I was like, 'This is what he wants to say and this is how he wants to express himself.'"

She first approached the score on the cello, an instrument she picked up when she was five years old. Music became Hildur’s preferred form of expression from a young age. It was all around her. Her father is a clarinet player, composer and conductor. Her mother is an opera singer. Her aunt plays the oboe and her uncle composes. Each of the musicians in her family deeply influenced the way she saw their instruments.

"I always regarded instruments as personalities, and that's one of the biggest influences on me, musically," she explains. "The personal connection that I have with the musicians I play with is almost more important to me than what they play or how they play."

It has also allowed her to experiment with sound. "Because there were so many instruments around, I was never shy about just making noise on whatever I was holding. That’s something that I still maintain today. I always find it fun to learn different instruments and get to know different types of acoustics."

Hildur, who was born and raised in Iceland, grew up listening to opera with her mother, as well as atonal and new classical music. But their mutual interests didn't end there: They would often watch When Harry Met Sally together. "We basically know every single word of that film," Hildur says.

And when she began her career in music, it was alongside her mother as well. "My first job was as a singing child Viking in a Viking-themed restaurant in my old hometown. I must've been around nine or 10. I would get dressed up in Viking clothes and I would go with a flock of Vikings to find tourists coming from the airport. We'd take buses of tourists to this natural resort, where I’d sing for them in a cave and feed them shark."

"I never made any conscious decisions about what kind of career I wanted within music," she explains. "It was so natural. I've always loved performing, and I've always loved building instruments and experimenting with electronics and writing compositions. I've always followed the train to wherever my curiosity leads me."

Hildur began writing solo music at the age of 18. She then started working on theater productions in Iceland, followed by films. "When I moved to Berlin, I started doing some German film productions and some European ones, and then, it led to the States," she recalls. "I ended up composing for film by following a ball that just kept on rolling. And now, it just so happens to be rolling into the Oscars, which is crazy. I'm probably the person that's most surprised about it."

The main difference between film and other mediums, she says, is the scope. "You’re communicating with so many people, and that’s really exciting," she says. "For me, music is about communication. When you’re playing for people, you’re communicating with them outside of words. It goes directly under your skin and straight to your heart no matter what."

That sentiment was at the core of her work on Joker. More than anything, she wanted it to resonate with viewers. It just so happened to resonate with the cast and crew as well.

"As I wrote the first themes, they were able to use it as they were shooting, so the music ended up influencing the performances on set," she says. The bathroom dance scene, for example, wasn't in the original script. Director Todd Phillips brought the music to Joaquin Phoenix, hoping it might inspire him. "And Joaquin just started to move. This dance was pouring out of him in response to the music. That really helped him find the transition from Arthur into the Joker."

Throughout the duration of filmmaking, Hildur worked from Berlin, while the rest of the team was in the U.S. But it remained an extremely collaborative process. "Todd sent me the script, then I wrote some music, then they used the music on set, then they sent me dailies so I could see how they were responding to it, then start making more music based on that," she says. "It was just this really lovely back and forth."

As a child born in the '80s, Hildur grew up with Batman. But she avoided referencing past works. "When you're writing music, you're really easily influenced, unconsciously, so if you listen to something, it can start to seep into what you’re doing without you even noticing it. I very deliberately tried to stay away from any outside influence." Instead, she found herself actively avoiding influence. "My son, who's seven, loves listening to Justin Bieber more than anything. So, that was fun to listen to, because I knew that he wasn’t going to inspire the score. It was safe."

Hildur first saw a completed version of Joker at its premiere during the Venice Film Festival in August. "It was just absolutely incredible," she remembers. "I think there was a 10-minute standing ovation." She hasn’t watched it since, but she's waiting for the moment she’ll get to look over and see fellow passengers watching it on a plane. "When you see everyone watching your film, it's quite funny. It’s a good reminder of how many people films touch."

A similar reminder came on January 13, when Hildur learned she'd been nominated for an Oscar for Best Original Score. When the news came out, "I was sleeping," Hildur says. "I basically woke up and turned on my phone, and it just exploded... I've just had the most surreal couple of months now. I still haven’t really registered this. I’m dreaming what's happening.”

The best part, she adds, is getting to know the other composers and feeling "so incredibly warmly welcomed" by their community in Hollywood. "The awards are just a bonus, but what's been really truly special is to get to put faces to all of this incredible art that we’ve seen throughout the years. That's been the biggest treat of all."

By Nadine Zylberberg