The cast of "It's Always Sunny in Philadelphia" will appeared on "Abbott Elementary." Here's how to watch, when it airs and what to know about the crossover.

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.

Kaitlin Olson may always be married to the hit sitcom It's Always Sunny in Philadelphia (in some ways quite literally, with ...

And that’s exactly what we got when The Gang from It’s Always Sunny in Philadelphia paid a visit ... The episode operates under the assumption that you already know who the Sunny characters ...

I’d met Quinta, and I knew she was a ... of their show through an entirely different prism when you see it on It’s Always Sunny in Philadelphia, and that version is much less family-friendly.

The 'Abbott Elementary' episode of the ‘It’s Always Sunny in Philadelphia’ and 'Abbott Elementary' crossover just aired. When will the ‘It’s Always Sunny' episode air? Here's what we know.

"It's always funny in Philadelphia," the promo promises ... "But I’m not gonna tell you with who or what or when, but it will be exciting, and I think it will change television as we know ...

The cast of It’s Always Sunny in Philadelphia made its way to the ABC ... and we want to do exciting things with comedy. And when you’re working with people like that, who are all on the ...

But they are both set in Philadelphia ... ‘Always Sunny?’ ” I was like, “You know what, despite being from here, no, I haven’t.” We binged, and it was hard to binge at that time. We ...

If you purchase an independently reviewed ... The ‘Abbott Elementary’ and ‘It’s Always Sunny in Philadelphia’ crossover episode (the first of two) is officially happening.

Here’s everything you need to know about the It’s Always Sunny in Philadelphia crossover episode. While we know for a fact that the Abbott Elementary episode of the two-part crossover event will occur ...