The actress attended a Hughes film class at the University of Southern California last week (ends29Apr11) and let slip that the stars of the two movies weren't necessarily her mentor's first choice.
She told students her break-out role in Hughes' Sixteen Candles cost John and Joan Cusack leading roles in The Breakfast Club - the siblings were slated to play bad boy Bender and outcast Allison in the school detention movie, but studio bosses wanted to shoot Sixteen Candles first, and the Cusacks were forced to bow out of the project.
According to EW.com, Ringwald explained, "Universal said 'We want to do this one first. We feel like it's much more commercial', which I think is funny because, well, I love Sixteen Candles, but I think Breakfast Club is a more interesting screenplay."
The actress feels Hughes never settled with the eventual choice of 'method actor' Judd Nelson as Bender - and their relationship was frosty at times, particularly when Nelson goaded her in rehearsals.
She said, "In my head, he was doing an acting thing. It didn't bother me but it bothered John a lot... I don't remember specifics about what he said, but he made some crack about Stevie Wonder and my father is blind. All of the sudden I turned and looked at John and his face was like stone.
"The rehearsal ended early and all of a sudden it blew up. I don't know what happened, but I'd heard he told Judd he was ready to put him on a plane."
Ringwald also revealed Rick Moranis was the first choice to play janitor Carl, but studio heads persuaded Hughes to use John Kapelos instead: "He decided it would be funnier if the janitor was a Russian immigrant.
"He (Moranis) came and filmed for two days, and Rick Moranis was hilarious, but it just did not belong in this movie at all."
And even Jon Cryer's iconic role as Phil 'Duckie' Dale in Pretty in Pink wasn't set in stone as pre-production on the 1980s film got underway - Michael J. Fox and Robert Downey, Jr. were both in the mix to play the character.
Fox dropped out to replace Eric Stoltz in Back to the Future and Ringwald admitted she had a lot of fun with Downey, Jr.
She recalled, "I remember Robert came in with a jacket decorated with Pez dispensers. He was just so funny and charming and charismatic, and we had this sort of sexual charisma together."