In 2018, Eilish confirmed that she has Tourette Syndrome and that she was diagnosed with the disorder when she was a child. The 16-year-old singer took to Instagram to set the record straight after compilation videos of her tics began to surface online. Tourette Syndrome is a neurological disorder that causes a person to have involuntary physical or verbal tics. In Eilish's case, she exhibits physical tics, not verbal.

No fair
You really know how to make me cry
When you gimme those ocean eyes
I'm scared
I've never fallen from quite this high
Falling into your ocean eyes
Those ocean eyes

When her mother Maggie appeared as a special guest on the Me & Dad podcast Eilish co-hosts with her father, talk turned to Billie's teenage infatuation with Justin Bieber and how she used to watch his 2012 "As Long As You Love Me" music video for hours and just cry and cry. "I just want to say, we did consider taking you to therapy because you were in so much pain over Justin Bieber," her mother joked.

12 of 14 tracks on the album shot into the U.S. Billboard Hit 100 when the album was released, and the other two songs ("!!!!!!!" and "Goodbye") charted in Canada.

When asked about her favorite movies during a 2020 Oscars red-carpet interview, Eilish said she "always loved scary stuff," especially The Babadook, a 2014 horror film about a troubled widow struggling to raise her disturbed six-year-old son who is obsessed with an imaginary monster.

And I know it makes you nervous
But I promise you, it's worth it
To show 'em everything you kept inside
Don't hide, don't hide
Too shy to say, but I hope you stay
Don't hide away
Come out and play

In January 2020, Billie Eilish was announced as the performer of the No Time to Die theme song, with her brother Finneas serving as co-writer as well as the track's producer. At the age of eighteen, Eilish is the youngest artist to record a Bond film title track.

Billie's favorite TV show is The Office, and she even used samples from one of the episodes in one of her songs. "When we made the beat for 'my strange addiction', it reminded me of the song they play when they do the Scarn dance," Eilish told MTV News. "I thought that was really funny, so we literally just ripped the audio from Netflix and put it in the song, not at all thinking that they would say yes to it and we'd be able to put it out. Also, it's about strange addictions, and The Office is mine, so..."

Los Angeles Mayor Eric Garcetti took to Facebook to encourage registration with Billie Eilish. He noted that every LAUSD High School was organizing a campus voter registration drive, and each participating school had the opportunity to win a live performance by Eilish. "As young people we have to own and use our power to make a difference. When we go into the voting booth, it's about deciding who will lead America into the future," Billie explained.

You should see me in a crown
Your silence is my favorite sound
Watch me make 'em bow
One by one by, one
One by one by (one)