The actors discuss playing best friends and roommates on FX's long-running comedy, which kicks off its 17th season Wednesday, and why "whenever Charlie does something, it titillates Frank."

There are shows that come and go, and then there’s It’s Always Sunny in Philadelphia, a sitcom show that somehow never really disappears. It slips under the radar at times, but it always comes back.

Plus, Charlie Day and Glenn Howerton tell TheWrap which other sitcom they'd love to cross over with after "Abbott Elementary."

In Wednesday's Season 17 premiere episode of "It's Always Sunny in Philadelphia," the "Abbott Elementary" cast gets to cuss — including the "c-word"!

It's Always Sunny In Philadelphia stars Charlie Day and Danny DeVito discuss when the long-running sitcom will come to an end as season 17 begins.

The It's Always Sunny in Philadelphia cast has thoughts on the worst things the gang has ever done, though some of their answers are a little out of left field.

Day and co-writer/star Rob Mac disagreed on whether or not cross over with "Abbott Elementary" and "The Golden Bachelor" in the new season

“They were like, ‘We don’t want to end it,'” Howerton recalled his co-stars saying. “And I was like, ‘Oh, well I can’t stop you.’ And then Seasons 13 and 14, I came back as an actor but I wasn’t in the writers room.”

FX’s It’s Always Sunny in Philadelphia is set to return on July 9, and fans are not only excited to see the new season, but to watch the crossover episodes.

"Beyond season 18, I don't know... it could quite possibly be the end," says the star and executive producer to THR about the longest-running live-action sitcom, now back with season 17.