As usual, before we get going here, I should warn you there are spoilers ahead (although no major ones), so proceed with caution if you want to know absolutely nothing and just bookmark this for later!
Now, for a little background, X was filmed in 2021 during the middle of the pandemic. Because they filmed in New Zealand, the filmmakers were required to go into COVID quarantine. During this time, writer-director Ti West co-wrote the screenplay for Pearl with star Mia Goth. And, because they were already set to film X, West basically pitched the brilliant idea of piggybacking off that production to do the prequel.
West explained to IndieWire:
“I came out of quarantine and I was like, ‘We’re already building all of this stuff, it’s COVID and we’re on the one place on Earth where it’s safe to make a movie. We have the whole crew from Avatar 2 who’s on break. We should make two movies.' The miracle of A24 was that they thought this was actually a good idea."