'Abbott Elementary' exclusive: details on crossover ep with 'It's Always Sunny in Philadelphia'

LOS ANGELES -- It's the TV crossover we didn't know we needed and On The Red Carpet has some scoop on the "Abbott Elementary" "It's Always Sunny in Philadelphia" episode.

Last week, "It's Always Sunny in Philadelphia" star Rob McElhenney posted a photo to Instagram confirming that his show will be doing a crossover with "Abbott Elementary."

Quinta Brunson had hinted there would be a crossover episode at San Diego Comic-Con back in July, not revealing with which show, but saying only that it would happen in season 4, which premieres this Wednesday.

On The Red Carpet exclusively caught up with Lisa Ann Walter, who is just happy that the cat's out of the bag.

"Well, now I can tell you that it's happening because for a long time we knew. I knew. I don't know if she told everybody but she told me because I'm Sicilian and I can keep a secret," Walter admitted.

"All I can tell you is we've already shot a bunch of scenes. I'm having the time of my life," she said.

We did manage to get a couple of hints about what's to come.

"I will tell you that as opposed to our normal 'Abbott' episode, it's unhinged. Those guys do not follow rules! I'm like 'Ok we have no rules today?! Duck suit is on! Consider the challenge taken, Charlie Day!'"

A duck suit? No rules? We can't wait to see what all this means.

No word yet on when the crossover episode will air. The season premiere of "Abbott Elementary" airs Wednesday at 9:30pm EST/8:30pm CST on ABC and streams the next day on Hulu.

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