While speaking with EntertainmentWeekly, Rick and Morty creators Justin Roiland and Dan Harmon revealed that Season 4 will have 10-episodes and that they’ve already started writing episodes for Season 5 to keep themselves on schedule.
ROILAND: “This new season will be 10.”
HARMOND: “I think it’s safe to say without fear of being wrong that the gap between seasons 3 and 4 will be the longest and last time that it’s ever so long that it’s ridiculous. I don’t know how fast we can do it, but I know it will never be this long again. There were so many things that had to be settled before we even started season 4, and it’s really safe to say — as Justin says — we’re literally writing season 5 while finishing season 4 just to force ourselves to commit to a certain schedule. Not to get anyone’s hopes up, but it is structured into our deal that if we’re going strong and fast there are options to deliver more episodes at a time.”
They also reaffirm that Season 4 will have guest voices from Paul Giamatti and Jurassic Park’s Sam Neill along with adding that Taika Waititi and Kathleen Turner will lend their voices as well.
RIOLAND: We’ve got Paul Giamatti. That’s a hot scoop. We got Sam Neill. Taika Waititi does a voice. Kathleen Turner.
Adult Swim had recently made a massive commitment for 70 new episodes of Rick and Morty that begins with Season 4, which will start airing sometime in November.
SOURCE: ENTERTAINMENT WEEKLY