Tom Hanks wasn't originally supposed to star in 'Big' - he replaced Robert De Niro, according to Elizabeth Perkins

• De Niro was originally cast in "Big" but didn't go through with it due to a scheduling conflict.
• "Big" star Elizabeth Perkins read opposite De Niro when she auditioned.
• "[De Niro] was more moody," she said. "It was more of a - a little more of a horror movie."

Believe it or not, "Big" was originally supposed to star Robert De Niro.

That's what Elizabeth Perkins, one of the stars of the classic 1988 comedy starring Tom Hanks as a boy who gets his wish granted and becomes a 30-year-old man, revealed to Andy Cohen on "Watch What Happens Live" on Wednesday.

Perkins, who was a guest on the show, was asked by Cohen if it was true that De Niro was originally the lead in the movie.

"Yes, Robert De Niro was actually cast in the role of Josh in the movie 'Big,'" Perkins answered. "It fell apart because he had a scheduling conflict, and then they went to Tom Hanks. It's like a totally different movie in my brain with Robert De Niro."

So, let's do the math. If De Niro went forward with the role he would have been around 44 years old - over a decade older than the age Hanks plays in the movie.

Perkins doesn't have to guess how different that movie with De Niro as the lead would have been, because she said when she auditioned for the role of the love interest, Susan, she read opposite De Niro.

"[De Niro] was more moody," she said. "It was more of a - a little more of a horror movie. Robert De Niro wandering around the streets of New York. What Tom Hanks brought to it was so much lighter."

-WWHL (@BravoWWHL) April 8, 2021

Clearly "Big" director Penny Marshall struck gold with Hanks in the role. The movie was a huge hit and earned Hanks his first-ever Oscar nomination.

But to be honest, we're a little curious what that version of "Big" starring De Niro might have looked like. We have a feeling he and Robert Loggia wouldn't have been playing around on a giant piano.