The Best Time Mac Broke Character On It's Always Sunny In Philadelphia

One of the telltale signs of a good comedy is when the jokes are so funny that even the actors can't hold in their laughter, and "It's Always Sunny in Philadelphia" is no exception. The show, which became the longest-running live-action sitcom in television history back in 2020, has become notorious over the years for having some of the most absurd, laugh-out-loud comedy in all of television.

It's a testament to the show's quality that even after all this time, the actors still struggle to keep their composure when reading their lines. FX has released plenty of compilations showing the characters breaking in almost every episode, and considering how ridiculous some of the lines and scenarios on the show are, it's a miracle they ever get through any scenes at all.

Normally, these kinds of compilations are the only places you'd be able to see the actors cut up, as all of these scenes are cut and shot until they're perfect. But there is one notable exception, where Rob McElhenney, who plays Mac on the show, broke character and the showrunners seemingly missed him laughing in the background.

In the Season 9 episode "The Gang Gets Quarantined," a severe flu outbreak sweeps through Philadelphia and forces Mac, Dennis (Glenn Howerton), Charlie (Charlie Day), Dee (Kaitlin Olson), and Frank (Danny DeVito) to hole up in Paddy's Pub to wait out the epidemic. Yet, despite their best efforts, each member of the gang falls ill and is confined to the Paddy's Pub bathroom, where their symptoms get worse and worse as the episode goes on.

When Mac first enters the bathroom, he finds Dennis and Dee already in the throes of horrific illness, with Dennis vomiting in the sink, and Dee as pale as a ghost. Apparently, watching his co-stars act so absurdly sick made McElhenney start to laugh in plain sight of the camera, as noted in this Reddit thread.

Hilariously, McElhenney's entire body is reflected in the mirror in this single reverse shot of Dee gagging. There's something so funny about the little grin on his face, and the way he's just kind of standing there, clearly not in character at all. We don't know if this was an oversight on the showrunner's part, or if they found it so funny that they simply left it in, but because he clearly thinks he's off-camera (and is just giggling in plain sight), it's one of the funniest bloopers that has ever made it on the show.