Be still, our Tiger Beat-ing hearts -- we almost had two hunky blonde '90s heartthrobs in "Now and Then." 

To celebrate the movie’s 20th anniversary -- the teen drama first hit theaters on Oct. 20, 1995 -- ET sat down with screenwriter Marlene King to get some inside scoop on the classic flick.

The one thing we didn’t expect? For her to shock us with the knowledge that Leonardo DiCaprio was originally cast in the movie.

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According to King, all of the roles in the beloved, coming-of-age film were cast with their first-choice actors, except for one.

"The one role that originally was different was Leonardo DiCaprio was going to play the Vietnam vet, but something happened and he had a conflict," she revealed. "I know, it's crazy!"

Despite DiCaprio's conflict -- which could have been the 1995 drama "Total Eclipse" -- King felt that they found a wonderful replacement for the role.

"Brendan Fraser was like a last minute swap for him," the "Pretty Little Liars" showrunner spilled. "But Brendan did such a good job, so it was all good."

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But, wait… Let's rewind: Leonardo DiCaprio as… the Vietnam vet?!

Naturally, when King revealed that DiCaprio was supposed to star in "Now and Then," we assumed he was cast to play Scott Womer, the ultimate boy next door.

However, that iconic role belonged to Devon Sawa, who teamed up, once again, with his "Casper" co-star, Christina Ricci, and Sawa became the big-screen crush we all longed to share an awkward, yet endearing, first kiss with.

"[Devon and Christina's kiss] is still one of my favorite scenes, and that was like a real memory," King dished of the self-described autobiographical film. "That was just like my first kiss when he kisses Roberta. That was like right out of my life's story and was so true to life."

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So did King know that Sawa would become the sex symbol for an entire generation of girls?

"No, we just knew that he was so cute!" King answered with a laugh. "I had watched 'Casper' because somebody had mentioned Christina for the movie, and we just thought he was so adorable. They just had such good chemistry together too."