Guess who! Zooey Deschanel is UNRECOGNIZABLE as she transforms into a blonde after being known for her recognizable brunette hair

She's famous for her long brunette locks and her retro-chic bangs.

But Zooey Deschanel completed transformed her appearance on Tuesday when she debuted a new blond look.

The 43-year-old New Girl star posed for a playful mirror selfie with a voluminous head of thick blond hair arranged in stylishly retro feathered curls.

'Who's she?' Zooey captioned her fun photo.

Although she easily pulled off the blond look, the actress looked like a different person with her dark hair, which has become the most identifiable part of her appearance in her decades in Hollywood and the music industry.

New girl! Zooey Deschanel, 43, was absolutely unrecognizable as she debuted new blond hair with voluminous, retro curls in a mirror selfie posted Tuesday to Instagram

New girl! Zooey Deschanel, 43, was absolutely unrecognizable as she debuted new blond hair with voluminous, retro curls in a mirror selfie posted Tuesday to Instagram

The singer appeared to be in a dressing room or an on-set trailer as she snapped her mirror selfie.

In addition to the blond hair — which was likely a wig, despite its impeccable dark roots — she put on a busty display in wha appeared to be a baby blue leotard.

Zooey wore it tucked into a casual pair of camouflage sweatpants, and she looked cozy in a puffy black down jacket.

A second mirror shot showed her surrounded by makeup brushes and a blond coworker with their back turned to the mirror.

Several commenters on Instagram reference her New Girl character Jess, as the theme song — which Zooey co-wrote and sings — ends with the lines, 'Who's that girl? It's Jess!'

They found her 'Who's she' comment reminiscent of the tag at the end of the song.

Zooey didn't give any hint of what she is filming that required the blond hair, but it may be for her upcoming guest appearance on the third and final season of Rose Byrne's Apple TV+ series Physical.

The series follows Byrne as she tries to launch her own Aerobics empire. The show is set in the 1980s in San Diego, California, a time and place in which Zooey's blond hair would have fit in perfectly. 

Guess who! 'Who's she?' Zooey wrote. She appeared to be posing in a makeup trailer on set, possibly for her upcoming guest role in Rose Byrne's 1980s-set Apple TV+ series Physical

Guess who! 'Who's she?' Zooey wrote. She appeared to be posing in a makeup trailer on set, possibly for her upcoming guest role in Rose Byrne's 1980s-set Apple TV+ series Physical

What a difference! Zooey is known for her iconic brunette locks, which she usually wears with stylish bangs
Consistent: She featured the look during the duration of her popular sitcom New Girl; seen May 22 in LA

What a difference! Zooey is known for her iconic brunette locks, which she usually wears with stylish bangs. She featured the look during the duration of her popular sitcom New Girl

Twenty years on: The last major time that she went blond was for her breakout role in 2003's Will Ferrell¿starring holiday comedy Elf (pictured)

Twenty years on: The last major time that she went blond was for her breakout role in 2003's Will Ferrell–starring holiday comedy Elf (pictured)

'Everyday she proves why people would’ve not recognized Clark Kent was Superman,' joked one person in her Instagram comments.

'HANG ON you are 100% stunning in this look!!' added Yellowjackets star Melanie Lynskey. Both played supporting roles in the 2002 thriller Abandon, which starred Katie Holmes, Benjamin Bratt and Charlie Hunnam.

Although it was certainly a major transformation for Zooey, her look on Tuesday was not the first time she has been a blonde, though the last time was 20 years ago.

Even though she is most recognizable for her brunette locks, her breakthrough role in 2003's Will Ferrell–starring holiday comedy Elf featured her with shoulder length blond hair, though in a dark shade that her new look.

She also wore lighter hair than she is best known for that same year in the acclaimed drama All The Real Girls, though her hair was still recognizably brown.

She has mostly stuck with the darker look and bangs ever since, though she did lighten her hair in 2019 for a Christmas performance as She & Him, her musical duo in which she sings and writes most of the songs while performing with the guitarist M. Ward, which Allure noted.

Last week, Zooey showed off some PDA with her boyfriend Jonathan Scott at the Los Angeles premiere of her new Max food show What Am I Eating?.

The Property Brothers star sweetly planted a kiss on her head as she beamed at the camera.

Tender moment: Zooey was spotted with her standard dark locks on May 22 as she walked the red carpet at the LA premiere of her Max food series What Am I Eating with Property Brothers beau Jonathan Scott

Tender moment: Zooey was spotted with her standard dark locks on May 22 as she walked the red carpet at the LA premiere of her Max food series What Am I Eating with Property Brothers beau Jonathan Scott

The future lovebirds met in 2019, when she and her sister Emily Deschanel joined him and his twin brother Drew for an episode of Carpool Karaoke.

In September 2019, a month later, she announced her divorce filing from her second husband Jacob Pechenik, and it was only a month after that that she and Jonathan made their relationship Instagram official. 

Now the two are closer than ever, and Jonathan has become an enthusiastic coparent to her two young children.

Her first marriage was to the Death Cab For Cutie frontman Ben Gibbard.