The 'Abbott Elementary' EPs talk jokes cut from 'Always Sunny' crossover, including backstories for Frank and Mr. Johnson.

Compendio: Frank is established as Dennis and Dee’s father when he first appears in Season 2 of "Always Sunny" — though the audience later finds out that he is not their biological father.

It’s always busy for the It’s Always Sunny in Philadelphia cast.

It's Always Sunny in Philadelphia is about to release ... However, the best character pairing was Frank (Danny DeVito) and Mr. Johnson (William Stanford Davis). These two are a natural fit because ...

The episode, which debuted on January 8, was a crossover with "It's Always Sunny in Philadelphia." More Gilles Mingasson/Disney The result is a series of hilarious moments, including Frank ...

We always knew that It's Always Sunny in Philadelphia's Frank (Danny DeVito) would easily match Abbott Elementary's Mr. Johnson's (William Stanford Davis) weird. But we just didn't know how much.

We're closer than ever to knowing a premiere date for "It's Always Sunny in Philadelphia" Season 17. Series co-creator and ...

Since 2005, the FX (and FXX) sitcom “It’s Always Sunny in Philadelphia ... illuminating — just how easily the “Sunny” characters fit in. Frank’s general weirdness pairs well with ...