The new movie Joker is a psychological character study of a 
lonely, disturbed man who turns violent. Dark, chaotic, unconventional —
 all descriptions that would make sense for a movie about one of the 
most infamous and unpredictable villains in comic book history. But in 
fact, director Todd Phillips wanted this Joker, played by 
Joaquin Phoenix, to inspire empathy. To give this comic book character 
human depth, director Todd Phillips brought in a composer who could 
transform darkness into sensitive musicality.
Composer Hildur Guðnadóttir has a few things in common with the character. She smiles and laughs a lot,
 and there's also a darkness inside of her. But instead of violence, the
 Icelandic cellist-composer expresses her darkness through music.
"My
 solo music started as a way to really look inwards, and to spend time 
completely by myself with an instrument, without any outside dialogue," 
Guðnadóttir says. "A lot of my music is kind of contemplative, and 
somehow that always tends to tilt on the darker side. My inner 
conversation is apparently quite dark."
Guðnadóttir has been schlepping her cello around and making music 
since she was 5. Before she was born, her pregnant mother named her, 
literally, "War, Daughter of God," and declared that she would be a 
cellist. "I'm Icelandic," she laughs. "We're all so dramatic."
The composer got into electro-acoustic experimentation, 
and made some angsty solo albums. She was also a frequent collaborator 
with fellow Icelandic composer, the late Jóhann Jóhannsson, and 
played cello on most of his film scores, including 
Sicario and 
Arrival. She co-composed one of his final scores, 2018's 
Mary Magdalene and has scored several films and TV series on her own. She recently won an Emmy for the HBO miniseries 
Chernobyl, a score she recorded in an actual decommissioned nuclear power plant, effectively turning the plant into a musical instrument.