Production has been slow on the Adult Swim series, which was originally scheduled to return last year.

“Rick and Morty” fans who have been waiting patiently for over a year to see new episodes are going to have to hold on a bit longer.

Speaking Sunday night at the Sundance Film Festival, Dan Harmon – who created the show with Justin Roiland – took responsibility for Season 3’s tardiness. The show was originally expected to return in 2016, but has been pushed back – with no air date yet.

“I’m so sorry,” Harmon told the crowd at YouTube’s pop-up space in Park City, Utah, where he sat down with IndieWire for a chat about his career. “I don’t have a release date for Season 3. It’s not that I know it and I’m not allowed to say it; it’s [Adult Swim’s] domain. What I will tell you is it’s late because of us, it’s late because of me.”

READ MORE: ‘Rick and Morty’ Season Three Sneak Peek: Watch this Cool Storyboard and Voice Actor Video

Harmon was brutally honest in taking the blame: “If Justin were here he’d agree. He and I would go, ‘Yeah, we fucked up,’ and it’s hard to put your finger on how we fucked up. ‘Rick and Morty’ keeps taking longer and longer to write, and I don’t know why.”

As “Rick and Morty” has turned into a critical darling and a fan favorite, Harmon admitted that there has been more creative struggles as he and Roiland map out the show. “We have fights all the time and then we have fights about why we’re having fights,” he said. “‘Well, we didn’t fight during Season 2, that’s why it’s taking longer! All this fighting! So OK, let’s stop fighting!'”

“Rick and Morty” last aired an original episode on October 4, 2015. But it’s become common for shows to take lengthy hiatuses as creators take time, rather than rush things, to get the creative right. The explosion in new outlets and platforms is also keeping writers and producers busy as they work on multiple projects.

For example, FX recently announced that Season 2 of Donald Glover’s “Atlanta” won’t air until 2018, due to Glover’s busy schedule. “Fargo” took 16 months between Seasons 1 and 2 as writer Noah Hawley worked on it. (Animation also usually takes longer to produce.)

To tide fans over, last fall Adult Swim premiered a series of claymation “Rick and Morty” shorts that mashed the characters up with classic films like “The Thing,” “The Fly” and “Honey I Shrunk the Kids.”

READ MORE: ‘Rick and Morty’ Take on ‘Ex Machina’ In Amazing Claymation Short

An Adult Swim spokesperson confirmed that there was “no premiere timing to share unfortunately – we’re still deep in production.” The show will reportedly air 14 episodes this season, although Adult Swim couldn’t confirm that count.

Harmon was mostly mum on hints about Season 3. “I don’t want to get murdered outside the building!” he joked. But he did tell the crowd that there won’t be another edition of the show’s “Interdimensional Cable” collection of faux TV shows, “but we’re doing something different.”

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