It was RobMcElhenney who first let it slip — via social media — that a long-rumored crossover between “Abbott Elementary” and “It’s Always Sunny in Philadelphia” was in the works.
If you look closely, RobMcElhenney, Kaitlin Olson, Glenn Howerton, and Danny DeVito are all wearing the same visitor badge around their necks. “It was very fun,” Kaitlin Olson said about filming ...