Silverstone - who was 19 at the time - said she was in Paris filming another movie when she received the bad news from Clueless' writer and director Amy Heckerling.
"I remember getting a fax from Amy Heckerling in my hotel in Paris saying something like, 'Oh well, we won't be making it now ... but maybe we'll make it in the future somewhere else'."
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Soon after, producer Scott Rudin gave it the push it needed.
"(He said) 'Absolutely we're making this movie'," Silverstone recalled. "And so we did. And it was a huge success. Then they (studios) were like, 'Oh, well, let's make a million more like it'."
Clueless hit the big screen in 1995 and went on to gross more than $27.3 million worldwide at the box office.