After much anticipation, the unlikely meeting of the two worlds unfolded on Wednesday's installment of "Abbott Elementary." ...

The Abbott Elementary & It's Always Sunny In Philadelphia crossover had hilarious character interactions, but it hid callbacks in its witty writing.

The star of the FX series also admits he was initially hesitant about the crossover concept as 'It's Always Sunny in Philadelphia ... then bringing in his bird law expertise.

There's something about FXX's Rob McElhenney, Charlie Day, Glenn Howerton, Kaitlin Olson, and Danny DeVito-starring It's Always Sunny in Philadelphia that's bothered me over the past few years.

There was a moment during the filming of the “Abbott Elementary” and “It’s Always Sunny in Philadelphia” crossover episode that blew Quinta Brunson’s mind. It was the first scene where ...