Starring Kirsten Dunst, Gabrielle Union and Eliza Dushku, the cheerleading flick helped catapult the sport to a fever pitch when it hit the big screen at the start of the millennium’s teen movie craze on Aug. 25, 2000. Now a cult classic, the summer blockbuster grossed $90 million worldwide and spawned five follow-up films, all of which went straight to video, and even a Broadway musical.

Following a champion team getting ready for competition, Dunst’s character Torrance takes over the Toros squad as captain for her senior year — only to find out that all of their award-winning routines were stolen from an underdog inner-city squad, the Clovers, led by Isis (Union).

But when it comes to the movie’s now-iconic cheer routines — often mimicked by high schools around the nation — some were actually originals. One memorable one, in particular, was created by actress Nicole Bilderback, who played mean girl cheerleader Whitney.

“I actually choreographed that,” Bilderback told The Post of the infamous “That’s alright/ That’s OK/ You’re gonna pump our gas someday” cheer. “I was being totally facetious, totally sarcastic and joking.”

“We spent about four or five weeks in cheer camp before we even started filming,” Clare Kramer, who played Whitney’s partner-in-crime Courtney, told the Post.

Watch the video above to find out more secrets from the movie, including the original title and ending, the brutal audition process — and who made a secret cameo in the film.