Why Mila Kunis Didn't Go Blonde for 'Luckiest Girl Alive' Role: 'Nobody Wants That!'

Taylor Hill/WireImage

Blonde was a dealbreaker for Mila Kunis when becoming the Luckiest Girl Alive.

The actress stars as Ani FaNelli in the new movie, on Netflix Oct. 7, which is an adaptation of author Jessica Knoll's 2015 bestselling debut novel. A brunette, Kunis wasn't the obvious choice for the part on surface level — Knoll recently admitted she envisioned the character as a "bottled blonde [who] then ends up paying $1,000 for highlights" but quickly was wowed by Kunis' performance.

At the Luckiest Girl Alive premiere held at The Paris Theater in New York City, Kunis, 39, joked to PEOPLE about why no major hair transformation was allowed.

"No," she says with a laugh. "Nobody wants that. Nobody wants that. That would not be good."

Cruel Summer alum Chiara Aurelia, who plays a teenaged version of Ani in flashbacks, adds that she would have been on board to mirror Kunis' locks whichever direction she decided to go for the role. "I was blonde before," says Aurelia, 20. "They actually dyed me to match Mila."

RELATED: See Mila Kunis Give a Powerful Performance as a Woman with Dark Past in Luckiest Girl Alive Trailer

Taylor Hill/WireImage From left: Jessica Knoll, Chiara Aurelia, Mila Kunis and Finn Wittrock

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Knoll, an executive producer who also penned the screenplay, tells PEOPLE why there was never any real discussions about Kunis going blonde.

"Once we knew it was her, we wouldn't have done that because I just think it would've been too distracting," she says. "I can only picture her that way because she wore that blonde wig at the end of the movie she did with Kate McKinnon [2018's The Spy Who Dumped Me]."

"I love that movie and she looks so great in it, but it looks like a costume," adds Knoll. "So, yeah, I think it probably would've been a little too distracting."

Hopper Stone/Lionsgate/Kobal/Shutterstock Mila Kunis and Sam Heughan in The Spy Who Dumped Me (2018)

In Luckiest Girl Alive, Kunis plays a woman who appears to have it all: a desirable wardrobe, an enviable Manhattan apartment, a coveted magazine job, a fast-approaching wedding to a wealthy fiancé. But a true-crime documentary inquires for an interview with her about a violent crime from high school, forcing her to reexamine her dark past and determine at what cost her "perfect" life is worth preserving.

"It's always fun to play someone very unpredictable," says Kunis. "I think we all put on a sort of facade whenever we're out or on social media and all of that, so I think we all have a little bit of this in us, and this is just the extreme version of it."

Finn Wittrock, who plays Kunis' husband-to-be in the film, explains why his costar could be playfully "sneaky" on set, going in and out of character on a dime.

Sabrina Lantos/Netflix Mila Kunis in Luckiest Girl Alive (2022)

"She's incredibly affable and easy to get to know," says Wittrock, 37. "It sort of sneaks up on you how much work she's actually done, because off-camera she's talking about her kids and making jokes and talking about her life, then suddenly it calls 'action' and she's so deeply into the part, to the point I was almost shocked: 'You really dug in deep here and pretended you were having a good time!' She's a sneaky actress."

About Kunis' strengths as a producer and lead actress, director Mike Barker says, "The thing about Mila is she is completely open. Mila has no secrets — if she doesn't like what you're thinking or doing, she'll tell you immediately."

Luckiest Girl Alive is now playing in select theaters and streaming on Netflix Oct. 7. The novel is available wherever books are sold.