On Twitter, we often see "Feel old yet?" memes, which often contain false updates on celebrities from the past.

For example, Mike Dimt from Green Day has not turned into Vladimir Putin, as the internet may lead you to believe, and Sid from the Toy Story franchise did not become actor Will Poulter as an adult.

You may not recognize her in her current career, but one grown-up child star has become one of the biggest rock stars in the world.

Taylor Momsen played Cindy Lou Who in the 2000 film How the Grinch Stole Christmas, which also starred Jim Carrey, Jeffrey Tambor, and Christine Baranski.

Momsen was only seven years old when she appeared in How the Grinch Stole Christmas and later gained fame for her role in the teen drama series Gossip Girl until 2012.

Eventually, she retired from acting to focus on her music career as the lead singer of the rock group The Pretty Reckless.

The band has released four studio albums, including their latest, Death by Rock and Roll, which was released last year and made it to the top of several charts, including the Billboard Top Album Sales chart.

The album debuted with 16,000 sales in the US and also reached the number one spot on the Current Rock Albums chart, the Record Label Independent Albums chart, and the Internet Albums chart.

In an interview with Today in 2020, Momsen said that her time on the set of The Grinch actually influenced both her acting and music careers.

Momsen reminisced about her experience working with Jim Carrey, saying: "I remember him being so kind and concerned, but also very methodical in his approach to acting."

"Even at that young of an age, I remember watching him and going, 'I'm watching an artist right now at work'."

"I think that people love The Grinch just simply because the core of the story is so sweet and it's so heartwarming and it has such a good message," she added.

"Aside from how amazing Jim Carrey's performance is and the theatrics that went into the shoot, just the way the film looks and moves and is edited is amazing in its own right."

Momsen said that the role of Cindy Lou Who also influenced her move into the music industry. She remembered feeling inspired after seeing the renowned composer James Horner at work in the studio.

"The thing that I remember the most that probably resonated with me to this day as an adult was the first time that I went into a recording studio and got to work with the amazing James Horner," she shared.

"And I'll never forget walking into this beautiful studio, with this immaculate console in front of me, and putting headphones on and singing into a microphone for the first time, singing 'Where Are You Christmas'."

"That was such an impactful moment in my life because it made me go, 'I wanna make music for the rest of my life. I love being in a recording studio'."

"I'm in my bedroom singing 'Where Are You Christmas' with the flashlight. I mean, essentially, that was my first music video. So I always get a kick out of that. And I remember thinking that was a really fun scene to film," she concluded.