After more than two decades of playing Charlie Kelly ... so that if an Always Sunny fan watches their show, it feels authentic to the characters they know,” he explained.

The star of the FX series also admits he was initially hesitant about the crossover concept as 'It's Always Sunny in Philadelphia ... to come up with something funny to do. Charlie Kelly fit ...

Back in early November, Ralph shared that her kindergarten teacher, Barbara, would be spending some quality time with Day's Charlie. "But you want to know what ... that be something that they ...

McElhenney’s Mac and his partners in business and crime Charlie (Charlie ... Even if we didn’t know this, the “Abbott" + "Sunny” team-up would still feel something special at a time ...

There was a moment during the filming of the “Abbott Elementary” and “It’s Always Sunny ... into something very, very, very good.” I think the other key pairing was Charlie and Barbara ...

Below, Day chats with THR about pulling off the crossover episodes, his initial hesitations about the idea and why he thinks the next season of It's Always Sunny ... something funny to do. Charlie ...