Alyson Hannigan's Signature Red Hair Isn't Her Natural Color & We're Stunned

Alyson Hannigan has taken on some iconic roles in her time, playing Michelle Flaherty in "American Pie," Willow Rosenberg in "Buffy the Vampire Slayer," and Lily Aldrin in "How I Met Your Mother." The one thing all those characters have in common? Red hair. But, surprisingly, Hannigan wasn't born with it. In news that's almost as shocking as Gwen Stefani not being a true platinum blond, Hannigan's natural shade is auburn.

The actor initially dyed her locks her signature red in the '90s when she landed her "Buffy" role, at the request of creator Joss Whedon. "[He] had us all over to his house. Charisma [Carpenter] and Sarah [Michelle Gellar] and I all had brown hair at the time. Joss said, 'All of your hair is kind of the same shade. Does anyone want to be red?'" she recalled to PopSugar. "I went for it. Eventually Sarah got more and more blond, but it was because we all had a brownish, auburn mane," she added. Clearly Hannigan liked the look, because, similar to the way Sarah Michelle Gellar incorporated Buffy Summers-inspired fashion into her personal style, Hannigan has stuck with varying shades of red on and off the screen. 

Hannigan showed us her natural color in 2024 when she posted the most adorable throwback Instagram photo. The snap showed her as a youngster with her light brown hair in braided pigtails. She also wore her natural hue in a snap from 1989, which confirmed her brown became darker as she got older.

Although she's known for her signature red hair, Alyson Hannigan isn't afraid to experiment with different hues. In March 2024, she gave an even bolder version of her usual color a go when she embraced a pink-leaning hue. "Hello midlife crisis, I think I like you," she jokingly captioned an Instagram post revealing her new look. Fans couldn't get enough of her bold style, with many comparing her to her most famous characters. "Are you Michelle or are you Willow," one person asked, while another commented, "This color is so Lily!"

The brave new 'do didn't last too long, though. When Hannigan posted an Instagram selfie with her family four months later (she shares two daughters with husband Alexis Denisof), she'd returned to a softer, red-brown shade that was closer to the amber hair trend that was huge in 2024.

Though we'll have to wait and see if the star ever returns to full-on red she rocked in the '90s, she's admitted seeing herself in "Buffy The Vampire Slayer" isn't always the most comfortable experience — partly because of her tresses. "It's a little like looking into an old yearbook. You know, 'Oh what was I thinking wearing that? Look at my hair! It's so weird!'" she told PopEntertainment.com. "But perhaps I can get over the vanity stuff and enjoy it."