Cynthia Erivo (left) and Ariana Grande in “Wicked.” Universal Pictures.

I’ll be staying away from theaters showing “Wicked” like they’re hospital Covid wards fresh out of masks.

Rendering: Adam Pardee/STAFF.

It appears singing in the theater is a thing, which makes sense because “Wicked” was a beloved Broadway musical, and people have always loved showing they know all the words to anything.

Heck, just the other day an old song from “Sesame Street” came on from the Muppets’ float during the Macy’s Thanksgiving Day Parade, activating some long-forgotten neurons dormant in my brain since 1973.

Suddenly and subconsciously, I started barking out every word, clearly against my will, forcing my 16-year-old to slowly back away from me with an uncomfortable half-smile on her face that said, “Let’s just placate the old man and keep things calm around here.”

But it’s become a problem (not me; I became a problem years ago). Some theater chains are asking people not to sing along, because there are some people on the planet who just want to eat their popcorn and see a movie without having to sit with a bunch of howling freaks wearing green face paint and giant pointy witch hats.

Halloween was more than a month ago, and that sort of behavior at movie theaters is still happily condoned at midnight showings of the “Rocky Horror Picture Show.” That was fun when I was 20. Now you can get off my lawn and stop singing while you’re at it.

That’s another thing the theaters are trying to ban: the green face paint. AMC, Cinemark and Regal have all said they need to be able to identify people in theaters for security reasons, which is kind of weird. I understand. Since the 2012 mass shooting at a Colorado theater during a showing of “The Dark Knight Rises,” theaters must be more security conscious.

But unless the witches are carrying long bags and have Rambo bandoliers across their chests, I think it’s safe to say “Wicked” fans aren’t dangerous.

Though that may not be the case when it comes to their fellow moviegoers’ ears.  If the audience is going to be singing, the rest of us need to be warned.

I’m scarred with a serious case of PSPTSD (public singing post-traumatic stress disorder), thanks to a tragic and horrifying experience at a Carole King show a couple decades ago. King was playing the Masonic in San Francisco with her piano, beautiful songs and lovely voice. It was a quiet show. If memory serves, she didn’t have a band and it certainly wasn’t loud.

Sitting next to my mom and I was the galaxy’s biggest Carole King fan, and he wanted the entire Western Hemisphere to know it.

At first it was a little irritating, until he got louder and louder to the point that I could no longer hear King. I was no longer at a Carole King show. I was at a performance of the world’s biggest Carole King fan with a voice cracking like Bart Simpson going through puberty.

Being afraid my mom would physically attack the guy, I gave him my best STFU look. Which made him sing louder. I didn’t think that was possible.

I repeated my look, but said “Dude … c’mon.”

He now looked at me while he sang.

“Look, I’m here to hear Carole King, not you. Shut the f%ck up.”

By then I was probably foaming at the mouth and looking vaguely desperate. So he took the hint. But the memory lingers.

Concerts are usually OK to sing along, because voices blend into the noise. But there’s not much noise in a theater; at least not enough to drown out that person in the audience singing like they’re gargling a cactus.

That’s not necessary.

I have a strange aversion to people singing in public who aren’t singers. Sing in the shower, sing in the kitchen, sing your kids to sleep (sing me to sleep). Just don’t start belting songs out in public.

What gets me—and there may not be any logic behind it—are everyday people who try to sing well in public (or when I’m trying to hear a movie or someone I paid to see sing). Even if you do sing well, don’t try. And whatever you do, don’t get the Mariah Carey vibrato going (and, sadly, there should be plenty of that going around the next month).

A strange loophole is karaoke. I used to be close to someone who was a karaoke DJ. I’d sit with her while she worked and hear some of the most terrifying noises come out of people’s mouths. But karaoke is supposed to be bad (I know there’s a subculture in which good singers develop rivalries and go against each other and whatever. I have no patience for that). But the God-awful singers never bothered me as much as the ones trying too hard.

It will take about a year for theaters to start booking once-a-week “Wicked: singalongs for all the cosplay nuts. By then it might be safe to watch on Netflix or HBO. I’ll just have to make sure I’m careful who watches with me. I may have to screen people.

Good luck in those theaters.