The only "bad guy" here is whoever burnt off Billie Eilish's hair!

The “Ocean Eyes” singer,17, debuted a new mullet hairstyle with bright green roots on Saturday at the 2019 LACMA Art + Film Gala, where she posed alongside stars including Naomi Campbell and John Legend.

The singer, who attended alongside her brother Finneas O’Connell, sported a head-to-toe Gucci look, wearing a pajama-style outfit with sneakers and accessorized with matching oversized sunglasses.

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Though fans praised Eilish’s modern take on the Joan Jett-style hairdo, the young star didn’t realize how her cut was being viewed.

“Mullet?” she asked a TMZ reporter who asked her about the haircut. “What do you mean mullet? You know what happened? Somebody dyed my hair and they burned half of it off. It’s not on purpose though. I’m growing that s—t out.”

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Although the mullet was by accident, it fits perfectly into Billie's edgy, boundary-pushing style, which includes oversized designer outfits, long, colorful nails and constantly changing hair color. (She's gone from green to silver to blue all within the past 12 months.

Eilish will be performing at The American Music Awards on Nov. 24 at the Microsoft Theater in Los Angeles, joining a bill that includes Lizzo, Dua Lipa, and Taylor Swift.

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We'll see if her mullet will make a return at the award show.