The star debuted a light blonde hue on Wednesday, after rocking her signature jet black shade with neon green roots at the Grammys on Sunday

It turns out Billie Eilish's drastic hair transformation on Wednesday wasn't actually that drastic.

In a since-deleted Instagram post that was screenshotted and reposted by social media users, the singer's hairstylist Lissa Renn revealed that she's been gradually lightening her client's jet black hue for over a month to prevent damage, leading fans to believe that Eilish was wearing a wig at the Grammy Awards on March 14.

"The process is real when you're doing it right. 6 weeks to get all the black of of her ends without damaging it, along with her following my strict haircare regime. We actually loved all the stages of lifting the color too but the end result is [fire emoji]," Renn wrote alongside a few photos of Eilish throughout the hair transformation process.

billie eilish hair changes
Credit: Getty; Billie Eilish/Instagram

Eilish seemingly confirmed fan theories on TikTok, posting a video of herself lifting up what appears to be a black and green wig on Wednesday.

On music's biggest night, the "Bad Guy" singer walked the red carpet with her brother and frequent collaborator, Finneas Baird O'Connell, in a pink, black and gray patterned button down shirt and matching flared trousers. She accessorized with white sneakers and a mask and bucket hat featuring the same multi-colored design. 

Billie Eilish
Billie Eilish
| Credit: Francis Specker/CBS via Getty

Eilish later changed into a crystal-embellished shirt, matching pants and a bejeweled headpiece to perform her hit song "Everything I Wanted" during the award show.

She sported her signature black hair with neon green roots for on both the red carpet and during her moody performance.

Then on Wednesday, the pop star posted a video showing off a warm light blonde hue, trendy curtain bangs and a shaggy layered cut, after asking fans to guess what color she would dye her hair next on her Instagram Story.

"did you guess correctly?" Eilish, 19, captioned the clip.

The Marilyn Monroe-meets-Lady Gaga inspired shade is already receiving raved reviews from her fans and Instagram followers, with one person calling the "Everything I Wanted " singer "AN ACTUAL BOMBSHELL." Eilish's post also broke the record for fastest to get to one million likes on the social media platform.  

The Grammy winner has been switching between all-over ink black and her signature black with neon green roots for the past few months (after sporting a light teal color at the beginning of 2019 and indigo blue before that).