Watch Taylor Momsen squeeze into original Cindy Lou Who costume from ‘How the Grinch Stole Christmas’ 25 years later

Oh, the Who-manity!

Taylor Momsen dug out her childhood Cindy Lou Who costume from “How the Grinch Stole Christmas” — and somehow managed to squeeze into it 25 years later.

The Pretty Reckless frontwoman, now 32, shared a video on Instagram Monday of herself trying on one of her original dresses from the 2000 holiday film for a festive photo shoot.

In the clip, Momsen models the frilly frock — complete with plates of Christmas cookies adorning the red-and-green plaid skirt —in a promotional shoot for her re-recording of “Where Are You Christmas?”

“Yes…that is my real Cindy costume from the Grinch movie 🥰 25 years later…it still (kind of) fits 🤣 what a surreal holiday season,” she captioned the post, tagging stylist Lindsey Hartman and other members of her team.

The rocker — who was just 6 years old when she filmed the Christmas classic alongside Jim Carrey — appeared delighted to slip back into her Who-ville wardrobe.

But while the Grinch’s heart may have grown three sizes, Momsen’s costume sure didn’t.

In the clip, Hartman helps the singer pull the kid-sized dress up her arms and over her head, while Momsen concedes her the sleeves may not make it past her biceps.

“You’re too jacked,” someone off-camera jokes.

Momsen spoke to Page Six on the 2025 VMAs red carpet in September about her ripped physique, crediting consistency and a boxing obsession for her chiseled muscles. “I work out a lot,” she told us. “I try to do something every day.”

Eventually, Momsen shrugs it down her arms for an off-the-shoulder look, and for the shoot itself, she’s re-styled it as a strapless dress topped with Cindy’s red-and-white fur-trimmed cape.

The “Heaven Knows” singer has been embracing her “Grinch” past this holiday season after years of ambivalence about the role that made her famous. In October, she released a rock ‘n roll version of the song her younger self performed in the film as part of The Pretty Reckless’ holiday EP.

She even reunited with Carrey, 63, in November for the first time since they filmed the movie. The pair crossed paths at the Rock & Roll Hall of Fame induction ceremony, where Momsen performed with Soundgarden and Carrey introduced the band.

Her relationship with the film hasn’t always been so merry and bright. In 2023, Momsen revealed on the “Podcrushed” podcast with Penn Badgley that she was bullied relentlessly after the movie premiered.

“First of all, ‘The Grinch’ changed my life in a multitude of ways — one of them being I was made fun of relentlessly,” she told her former “Gossip Girl” co-star.

“Every time I would start a new school or go somewhere else, I don’t even think the kids knew my name,” she recalled. “I was just ‘Grinch girl.'”

It’s taken time, but she’s since come full circle on the film and now embraces the nostalgic holiday cheer it brings.