Twenty years ago, director Mark Waters (“Freaky Friday”) and writer Tina Fey of “Saturday Night Live” captured a pop culture moment with their smart teen comedy “Mean Girls.” The film explored teen angst in the year when Facebook had just been invented and diversity had yet to become standard practice in the industry. The film starred Lindsay Lohan as new girl in school Cady Heron, along with stars-in-the-making Rachel McAdams (“Are You There God? It’s Me, Margaret”) as queen bee and “mean girl” Regina George and Amanda Seyfried (“Mank”), along with Lacey Chabert (“The Wedding Veil Journey”) as Regina’s sidekicks Karen and Gretchen.

This new “Mean Girls,” like the new “The Color Purple,” is not a remake. It is an adaptation of the 2018 Broadway musical version of the 2004 film, and it is a bit of a hot mess. During chaotic production numbers I thought fights had broken out. Beginning with the first of many forgettable and/or derivative songs by composer Jeff Richmond, Fey’s husband, and lyricist Nell Benjamin (“Legally Blonde”). Cady is a home-schooled young woman who has lived with her mother (Jenna Fischer) in Kenya before returning to the U.S.. We are introduced to Cady and her predicament by fellow students Janis (Auli’i Carvalho) and Damian (Jaquel Spivey). Some in the audience might wonder why these people sing directly into the camera. Let’s put on a show.

After not finding empty seats in her new classrooms, Cady (Australian actor Angourie Rice, “Spider-Man: Homecoming”) tries to sit at the “Mean Girls” table in the cafeteria and is instantly rebuked by Regina George (Renee Rapp of one of the Broadway productions), and we are off and running.

Fey, who wrote the musical’s book, returns as sympathetic teacher Ms. Norbury. Tim Meadows is also back as school principal Mr. Duvall. Instead of Amy Poehler as Mrs. George, we get a delightful Busy Philipps. In the role of the romantic interest Aaron Samuels is the appealing American actor Christopher Briney (“The Summer I Turned Pretty”). In the roles of Gretchen and Karen we now have a frantic Bebe Wood (“Love, Victor”) and Avantika, who seems high on her lip gloss.

The cast is problematic. Rice is a bit of a dud. Rapp is much taller than Rice, making Regina appear to be the evil giant of the tale. The songs are almost child-like. In one case, the lyrics rhyme the words (?) “nonplussed” and “calcu-lust.” Cady fall for Aaron. But she is told by Karen and Gretchen that he is one of Regina’s exes, and exes are out of bounds for the Plastics (which is what the Mean Girls are called). At a party, Regina finds out Cady likes Aaron and pretends to want to get back together with him. Mean, right? Interesting? Not so much. I believe the song sung in this scene sounds so much like a Billie Eilish tune that I sang the lyrics to “No Time to Die” along with it.

To make matters worse, the film’s directors Samantha Jayne and Arturo Perez Jr. bring back the shaky cam, as well as changing aspect ratios, in some cases recreating the shape of a smart phone. Jon Hamm appears as a teacher who won’t allow Cady to go to the restroom (not funny) and then disappears. “Mean Girls” is an exercise in what a mediocre cast can do with material that was once raised to its heights by a great one. It’s a valuable lesson. But we should not have to pay to learn it.

(“Mean Girls” contains profanity, teen drinking and sexually suggestive material)

“Mean Girls”

Rated PG-13. At the AMC Boston Common, South Bay, Causeway, Alamo Drafthouse Seaport, Landmark Kendall Square and suburban theaters. Grade: C+