How Billie Eilish has transformed her style with colorful hair, from green roots to a blonde bob she regrets

In 2018 — just two years after releasing her first song, "Ocean Eyes" — Eilish sported long, gray strands at Nylon's Young Hollywood party.

She wore the color in long, straight strands with a middle part — her signature style at the time.

At the 2019 iHeartRadio Music Awards, Eilish walked the red carpet in an all-black outfit that matched her newly dyed black hair.

As for style, she continued to wear it straight with a middle part.

She originally added the glowing color across her head in the summer of 2019, from her bangs to the ends of her hair.

Around that time, Eilish was also seemingly a fan of space buns.

Months after debuting her green hair, Eilish changed the style so that the green only covered her roots.

Some fans took issue with Eilish making the color her signature and said on Instagram that they felt it was time to change it up.

But the "Bad Guy" musician stood by her hair-color choice.

"It's called not being depressed anymore pls just be happy for me," Eilish responded on social media. "This is the longest I've had the same hair color since I was 13 & that's on mental stability and growth leave me alone lsjdkksjdjs."

Speaking with Elle in September 2021, Eilish said she chose the color because she "couldn't go anywhere" with her green roots.

"I wanted anonymity," she told the publication. "I went to a park with a friend, and I was like, 'No, I can't take off my hood!' I was terrified of the paparazzi and these stalkers I've had. But my friend was like, 'Don't worry. You're OK. Nothing's gonna happen.' And I took my hood off, and I felt like a new person."

But despite the freedom she originally felt, Eilish later said the color wasn't the best choice for her.

"I feel sexier when I dress masculine. I didn't feel sexy for one second of being blonde," she told Highsnobiety during a 2022 interview. "When I was blonde, people treated me differently. People completely changed their demeanor."

She then told Rolling Stone in April that she also didn't recognize herself with the light hair color.

When she attended the Variety Music Hitmakers brunch, Eilish's hair was dyed a chocolate shade of brown.

She wore it styled straight in a blunt bob with layers and curtain bangs.

Her new hair color was as black as the dramatic Gucci gown she wore on the red carpet. And while it was still cut short, Eilish had it styled with side-swept bangs and curled ends.

Eilish's new red roots were on display when she performed at Lollapalooza in Chicago at the beginning of August 2023.

She also shared a photo of her hairstyle on Instagram with the caption, "remember me?" — seemingly commenting on her former bold hairstyles.

She debuted the jet-black shade at the 2024 People's Choice Awards in February and has been rocking the dark look in a silky blowout ever since.