'Rick and Morty' season 3 spoilers, updates: Mr. Meeseeks to reappear? Vin Diesel to voice a character?

While the creators of "Rick and Morty" have yet to disclose an official airdate for the animated series, it's definitely coming back this year. Dan Harmon and Justin Roiland are keeping mum on the release date, but they have been sharing the third season's storyline whenever possible.

At this year's San Diego Comic-Con, Dan Harmon talked about his dream guests for the series, and topping his list is "Fast 8" star Vin Diesel. Apparently, should they get the actor to agree to a guest role, he would be playing D&D, but the creators know it's a long shot. What they assured is that a season 1 fan-favorite character would be making a comeback on "Rick and Morty" season 3.

Mr. Meeseeks, the blue alien who appeared in one episode of the first season, is coming back to "Rick and Morty's" world.

"However, we can also do an episode where it's not about that as a topic and just have him like Dr. Seuss, use him as a tool," Slashfilm quoted Harmon as saying. "I guess that's some kind of guy that says, 'I'm Mr. Meeseeks' and does his thing."

In that same interview, Roiland said they're thinking of adding an episode to "Interdimensional Cable," the show's sub-franchise. However, he said it's still on the drawing boards, as it isn't easy to make.

Roiland teased of a different element, something unheard of before, that they are contemplating on adding to the show. Apparently, such would turn the show to "something amazing," but he won't go into the details for fear of giving away spoilers.

The duo of Harmon and Roiland likewise explained the seeming delay of the season 3 premiere, saying its development present some creative challenges to the entire team.

"Episode 301 is the least compatible with the new viewer because we have so many loose ends to tie up," Roiland explained (via Collider).

What's certain about season 3's premiere episode is it would address what happened next to Morty and his family after they were sent back to earth, as well as Rick's whereabouts.

Stay tuned for more news and updates about "Rick and Morty" season 3.