Which celebrity redheads have natural red hair?

From Julianne Moore to Emma Stone to Christina Hendricks, Hollywood’s full of flame-haired beauties — but not all of them are genuine gingers. In honor of National Redhead Day, we’ve rounded up some of the most famous auburn-haired celebrities, both natural and not. Getty Images

Julia Roberts skyrocketed to superstardom as a redhead in “Pretty Woman” and “My Best Friend’s Wedding,” but it’s not her natural hue. “My hair is naturally blond — kind of a dark blond,” she told David Letterman in 1989. Getty Images

One of Hollywood's few natural redheads, Julianne Moore's made her bold hair hue one of her calling cards (along with Oscar-worthy performances, of course).

One of Hollywood’s few natural redheads, Julianne Moore’s made her striking hair one of her calling cards (along with Oscar-worthy performances, of course). Getty Images

Lucille Ball was born a brunette; it was late hairstylist Sydney Guilaroff who transformed her into the flame-haired beauty we know and love.

“A lot of people think of the color as red, but [her hair was] a golden-apricot color,” Irma Kusely, who did her hair for “I Love Lucy,” told the Television Academy Foundation. “I used regular hair dye [to color it], and then a henna rinse, which she was famous for. She had a safe of [the henna] in my garage.” Getty Images

Christina Hendricks rocketed to superstardom as the fiery-haired Joan Holloway on “Mad Men,” but believe it or not, the actress’ natural mane is actually blond. Getty Images

There are no “Big Little Lies” when it comes to Nicole Kidman’s hair color: The screen icon’s a true redhead. AFP via Getty Images

Emma Stone may be one of Hollywood’s hottest redheads, but she’s actually blonde. Judd Apatow initially asked her to dye her hair for her role in 2007’s “Superbad” — and while she occasionally goes lighter, the star’s returned to red time and time again ever since. Getty Images

“Mean Girls” heroine Cady Heron wasn’t lying when she told Damian her hair color was natural; Lindsay Lohan’s a born redhead. Getty Images

While it may seem as though Florence Welch has been red her entire career, the fashionable Florence + The Machine hitmaker started out a brunette. Patrick McMullan via Getty Image

“The Help” star Bryce Dallas Howard doesn’t need any help when it comes to her hair — because that red’s the real deal. FilmMagic

Talk about a stark difference; natural blonde Sophie Turner went full-on ginger to play Sansa on the beloved HBO show, but has since returned to her usual hue. Getty Images; WireImage

Unlike her “Riverdale” co-star KJ Apa, Madelaine Petsch (aka Cheryl Blossom) rocks her natural cherry-colored hair on the hit series. FilmMagic

Amy Adams may have rocked auburn hair for the better part of her movie career, but her natural color is blond. WireImage; Getty Images

You’ll never have trouble spotting “Now You See Me” beauty Isla Fisher, thanks to her naturally ginger locks. FilmMagic

Miranda Hobbes, a natural blonde? Believe it — actress-turned-politician Cynthia Nixon dyed her hair red for her role on “Sex and the City.” FilmMagic; WireImage

The 23rd Annual Critics’ Choice Awards – Red Carpet

Jessica Chastain’s signature scarlet waves? Totally natural. Getty Images for The Critics’ Ch

Debra Messing captured our hearts as a redhead on “Will & Grace,” but the star’s actually a brunette. Getty Images

She’s experimented with both blond and brunette over the years, but Kate Mara’s naturally ginger. Getty Images

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