It's Always Sunny In Philadelphia's Charlie Day Joins Toucher & Rich

BOSTON (CBS) -- It's Always Sunny In Philadelphia remains one of the best and funniest shows on television, and Charlie Day is a big reason why.

The Rhode Island native joined 98.5 The Sports Hub's Toucher & Rich to discuss Sunny and his new movie, Fist Fight, and was as entertaining as always. He said even as the show hits its 12th season, there is no talk of slowing down.

"There's always the conversation of 'how long can we keep doing it?' But it's interesting, I can't tell you the reaction I'm getting [for the new season]. There are more and more people coming up to me and saying they love this year," said Day. "The ratings are actually higher, through the roof, so you look at it and say 'why would I stop?' We're still doing funny stuff, the fanbase is still there and it's still a fun job to have. It would be crazy just to quit."

Day said he and Rob McElhenney and Glenn Howerton (Mac and Dennis, respectively) put together the first season of Sunny on their own, and while FX liked it, they wanted some star power on it. So they pushed them to add Danny DeVito, who was a fan of the show.

"We did one season and nobody watched it. It was like seven episodes and they said, 'Look, if you could get a big name on we'll bring you back.' They had just put Glenn Close on The Shield and they got a bit ratings bump. Fortunately DeVito's kids had seen the show, and he had seen it too, and we kind of went to him hat in hand, said we'd write you a funny character and thank god he said yes," explained Day.

And it's a good thing they did, because Day and DeVito provide some of the funniest scenes in the show.

"Something about Danny and I, we just kind of clicked. Just that combo of people felt funny, so it was good to write to it. It was pretty organic," he said. "I can't even rage as hard as that guy. Hes so fun to hang out with, and then there are sometimes where it's like 'you need to slow down; you're 70 years old.'

"He's bulletproof – that or the bullets fly right over him," Day joked of DeVito.

Day explained that the shorts seasons (they've been doing just 10 episodes per season) is so they don't experience a "burnout factor."

"We don't want to do so many episodes that we run out of good material. It gives us the rest of the year to do movies," he explained. "It keeps the show fresh."

Day also talked about McElhenney getting fat for one season, and his "surreal experience" working with Ice Cube on his new movie Fist Fight: