The Real Reason Danny DeVito Joined The Cast Of It's Always Sunny

It's Always Sunny in Philadelphia has one of the best casts on television, but the show actually launched without its biggest star.

The long-running show — which was renewed through season eighteen in December of 2020 and has broken records as the longest running live-action television series in history — tells the often deranged story of Paddy's Pub, a downtrodden and seriously unsuccessful bar in Philadelphia, and its proprietors, whose japes and schemes are constantly going awry. Twins Dee and Dennis Reynolds (Kaitlin Olson and Glenn Howerton), Ronald "Mac" Macdonald (Rob McElhenney), and Charlie Kelly (Charlie Day) begin the show running this clearly awful bar, and it seems impossible that Danny DeVito — who plays Dee and Dennis' father Frank — wasn't with the show from the very beginning.

However, DeVito, who was already a beloved fixture on the big and small screen by that point, didn't actually join the series until its second season. Here's the real reason why Danny DeVito joined the cast of It's Always Sunny in Philadelphia.

The truth is that this little show that could, which shot its first season on a shoestring budget, faced cancellation in its early days at FX... and ultimately, DeVito saved it. In an interview with late night host Stephen Colbert in February 2020, McElhenney revealed that the network essentially ordered them to let the star join, even though McElhenney was against it at the outset.

"He didn't come on until the second season," McElhenney explained. "The first year, we made seven episodes and they aired the show on Wednesday nights around 10:30 on FX, which was a new channel at the time. They had no other comedies, no other lead-ins. We got a call the next day after the first airing [...] and the President of the network, John Landgraf, said, 'nobody watched the show.'"

Because FX didn't have much of a marketing budget but wanted the show to survive, they suggested adding DeVito, a big name star who was friendly with Landgraf. "We said no," McElhenney recalled. "I said no thank you. We don't want Danny DeVito. [...] It's nothing personal against Danny DeVito. I grew up watching Danny; he's a legend, he's incredibly funny and we love him. We thought we had something really special, and we really thought that maybe bringing a movie star on would ruin the chemistry. And [Landgraf] was like, 'okay, well, then we're going to cancel the show.' And I said, 'Get me Danny DeVito! As quickly as possible!'"

"The only thing more important than chemistry on a TV show... is the TV show," McElHenney joked. Clearly, DeVito has fit in perfectly over the course of It's Always Sunny — and apparently, he saved the show entirely.

The upcoming fifteenth season of It's Always Sunny in Philadelphia will air sometime in 2021, and the first fourteen seasons are streaming on Hulu now.