The movie "Mean Girls" is based on a nonfiction book.

"Mean Girls" came out in 2004 and quickly became a hit.

Regina George, portrayed by Rachel McAdams, is the queen of The Plastics and reigns supreme at school. However, her power is challenged when Cady Heron, played by Lindsay Lohan, arrives and starts to undermine George's authority within her clique.

Since its initial release, the movie has gained popularity among new generations and is now celebrated annually on Oct. 3, which is derived from a famous line in the film.

Here are some lesser-known facts about "Mean Girls."

A sequel to "Mean Girls" was released twenty years after the initial film.

The 2024 adaptation of "Mean Girls" is a musical adaptation of the original film. Although it shares some similarities with the original in terms of characters and storyline, the music in the film is vastly different from the original version.

The 2024 film features a nearly entirely new cast, with Reneé Rapp playing George and Angourie Rice portraying Heron.

Some actors, including Tina Fey and Tim Meadows, reprised their roles in the 2024 film.

In the film, Ms. Norbury, portrayed by Fey, is the author of "Mean Girls."

At the time, the comedian was best known for her work on "Saturday Night Live," where she collaborated with Lorne Michaels on "Mean Girls."

Mark Waters, who had previously collaborated with Lohan on "Freaky Friday," directed the movie.

Despite its comedic portrayal in the movie "Mean Girls," the film was inspired by a real-life account.

Queen Bees and Wannabes" is the book that inspired "Mean Girls.

The book was written in 2002 by Rosalind Wiseman.

The classic line in the film has made Oct. 3 a day to celebrate the movie.

In the movie, when Heron converses with Aaron Samuels, her ex-boyfriend and George's former crush, he inquires about the date, to which she replies, "It's Oct. 3."

This scene is short, yet memorable.

"Mean Girls" Day is celebrated on Oct. 3, even though not everyone has seen the entire film.

In "Mean Girls," Amy Poehler portrays the "cool mom" character of George.

In real life, Poehler wasn't much older than her on-screen daughter.

McAdams is only seven years older than Poehler.

The "Jingle Bell Rock" performance was not the only one that captured the audience's attention.

The rap by Rajiv Surendra, who played Kevin Gnapoor (Kevin G), was a standout thanks to the help of Tina Fey and Amy Poehler.

The rap was crucial to the movie, and Fey and Poehler played a significant role in helping Surendra perfect it. A video of Poehler attempting the rap herself circulated online, with Fey and Lohan in the background.

The cast of "Mean Girls" could have looked vastly different.

Both Amanda Seyfried and Lohan were interested in playing the role of George, but ultimately landed their respective roles of Karen Smith and Heron.

Blake Lively was almost a gossip girl and a mean girl. She was a top choice to play Smith during the casting process.

"Seyfried recounted her first trip to LA with her mother, which was an exciting experience. During the trip, she met Lacey Chabert for the first time, and Lindsay Lohan was present. Additionally, Blake Lively portrayed Karen, while Seyfried took on the role of Regina."

In the end, Lively did not secure the role, and Seyfried ultimately played Smith. Tisdale also auditioned for the film.

The original intent of 'Mean Girls' was not for a young audience, but it has since become a favorite among preteens.

The original R-rated movie was later given a PG-13 rating by the Motion Picture Association of America.

The final version of the film contained less vulgar scenes and swearing than the original cut, specifically by McAdams' character.