Billie Eilish and Jimmy Fallon
Billie Eilish and Jimmy Fallon

As her sophomore album burns up the charts—debuting at #1 on the Billboard 200 in the U.S. this week—Billie Eilish dropped in (virtually) to The Tonight Show to chat with host Jimmy Fallon and perform the title track.

“I wanted it to feel very specific. I wanted it to have a real…feeling to it and a real aesthetic to it, I guess,” she said of Happier Than Ever.

Fallon also asked the singer about directing her own music videos and shared a behind the scenes clip of Eilish filming the video for her single “NDA.” “I feel like when you have your own idea and you know what you want, sometimes it’s just the best way to go about it is to just do it yourself. Even though it takes much more out of you,” she said.

The pair also discussed synesthesia, a neurological condition that Eilish says causes her to associate certain things with random colors, shapes, numbers and sometimes smells. “It doesn’t mean anything, but it inspires a bunch of stuff,” she explained. “So, all of my videos have to do with synesthesia. All of my artwork, everything I do live, all the colors for each song, it’s because those are the colors for those songs, specifically.”

Naturally, Eilish also associates people with specific colors and shapes as well. In Fallon’s case it’s a vertical brown rectangle. “So, your name’s Jimmy: J is brown to me. I don’t know why,” she told the host. “And you also feel like that color to me.”

Catch Eilish’s performance of “Happier Than Ever” below.