She matched her hair to her outfit in the photo, wearing the black Chicago Bulls jersey trimmed with red and white piping that she wore for her performance at Lollapalooza on Thursday.

She debuted her new hair color at Lollapalooza on Thursday.Getty ImagesShe wore a black-and-red jersey to go with her new hair.Getty Images for ABAShe went Blond Barbie for her music video off the film’s soundtrack.Instagram/ Billie Eilish

The Grammy winner piled on plenty of silver chains to accessorize her sporty outfit, adding a pair of black sunglasses with tinted red lenses.

Fans were digging the new hairstyle, like one who wrote, “ROOT ERA IS BACK ROOT ERA IS BACKKKK”

“Just s—t my pants ! ” TikTok personality Nicolas Sturniolo wrote, while another fan added, “OMFG. just fell to my knees. NEW ERA??!!!!

Eilish is no stranger to a bold hair color, having switched up her style many times over the years — and even had to cut her hair into a mullet due to the damage her frequent dye sessions have caused.

Eilish wore neon green roots for nearly two years.Instagram/ Billie EilishThe star went through a blond era a few years ago.Instagram/ Billie EilishThe singer was known for blue hair in the early days of her career.Instagram/ Billie Eilish

While the pop star tried silver and lavender shades, she was known for her signature blue hair at the beginning of her career – despite telling Buzzfeed that the hue was her “least favorite color.”

In 2019, the “Ocean Eyes” singer went on to swap the shade for black hair with neon green roots similar to this week’s red dye job, prompting fans’ excitement over Eilish going back to her “root era.”

The chart-topper rocked the green style until 2021 when she nearly broke Instagram with her platinum blond locks, bringing in a record-setting 1 million likes in six minutes when she posted a pic of her new hair. However, the star said she “didn’t feel 𝑠e𝑥y for one second” as a blonde.

Since then, Eilish has swapped blond for brunette — secretly going red for a week and wearing a plethora of wigs to ease in the dramatic transition — and gone back to black, but it seems she’s “Happier Than Ever” with a colored root.