It's still unclear whether everyone's favorite sociopath, Dennis Reynolds, will return to It's Always Sunny in Philadelphia in Season 13, but series costar Charlie Day says he wouldn't want to do the show without actor Glenn Howerton.

Day recently addressed the topic in an interview with the Huffington Post, saying,  "we really never want to do the show without Dennis." However, should Howerton move on from the series, Day envisions Dennis in at least part of It's Always Sunny's forthcoming season on FXX.

"There is a possibility that maybe we would have Dennis in part of a season, not a complete season," Day said. "I think we would still do a great season. There is a possibility that we have Dennis for an entire season, which would be fantastic."

This year, NBC picked up a pilot called A.P. Bio, in which Howerton stars alongside Patton Oswalt. Created by Seth Meyers and Lorne Michaels, the show  reportedly would cut down heavily on Howerton's time to work on It's Always Sunny, leading to concerns that he might not return to the show.

Additionally, at the conclusion of It's Always Sunny's most recent season,  Dennis had a breakdown that had him proclaiming  he "can't do any of this s- anymore," presumably meaning the Gang and all of Philadelphia. So, in that sense, his return to the series remains open-ended.

But don't expect Day to be anything like the character he plays.

"I apologize to anyone who's under the delusion that I actually am my character from It's Always Sunny in Philadelphia," Day said. "For anything I happen to do in my life that does not directly correlate with the behavior of that character that displeases the fans, I truly apologize; however, for anyone who is that delusional, I think, get over it."

A premiere date of Season 13 has not yet been announced. However, most estimates put the debut in late 2018 or early 2019, thanks to production delays.