Here's some background and inside jokes to help fill in some of the gaps for viewers who don't watch both Philly-based shows.
The star of the FX series also admits he was initially hesitant about the crossover concept as 'It's Always Sunny in ...
In true Abbott Elementary fashion, “Testing” was full of shenanigans. Janine found herself reeling after her second graders ...
The Abbott Elementary & It's Always Sunny In Philadelphia crossover had some ridiculous rivalries, but Charlie got a ...