The secret in Romy & Michele's High School Reunion that changes everything.

Just when you think you know everything about a cult-classic film, new information is revealed and you suddenly realise that really, you knew nothing at all.

Such is the case for Romy & Michele’s High School Reunion, which is celebrating 20 years since its original release this week.

Known for iconic moments like asking a roadhouse waitress if they offered a "business woman special", claiming they invented Post-Its, and a three-way dance scene with Alan Cumming that no self-respecting cinephile could ever forget, it turns out there's one significant secret we never knew until this week.

And that is that the characters of Romy and Michele were based on REAL PEOPLE.

According to the film's scribe and co-executive producer, Robin Schiff, “They were loosely based, just visually, on these girls I used to see going into a club on Sunset Blvd."

In an interview with Vanity Fair earlier this week, Schiff continued, “You’d see these two friends, and they looked like they got dressed together and were wearing different versions of the same thing.”

Having first written what would eventually become Romy & Michele's High School Reunion as a play in 1987, Schiff said that from the moment her story of "two young Valley Girls" hit the stage it was an instant hit met with “a huge laugh and applause”.

“I’m standing in the theatre going, 'Why?' I’m still fascinated what made them applaud just by seeing them,” she said.

Whether or not Schiff ever made contact with the women, or they ever knew it was them who the iconic film was based off, we'll probably never know.