Kirkman fielded questions from fans at a panel during Walker Stalker Cruise 2018, where an attendee inquired about the chance the former sheriff's deputy never really woke from his coma: "Zero. Next question," Kirkman joked.
"Yeah, that comes up from time to time. That would be a terrible story," he said.
"I think that's been done in a lot of things, but he is definitely not in a coma, I promise. Like, he'd wake up and Negan would be the plumber. He'd be like, 'Oh, you were there. It was so weird.' Yeah, that'd be awful. Judith is a ghost. Yeah, Rick is definitely not in a coma."
Kirkman added he has to address the question like "every two years," saying, "I have to come out and be like, 'he's not in a coma, everybody!' And then that makes the press rounds, and people are like, 'whew,'" Kirkman said.
"Then two years pass, and they're like, 'is he in a coma?'"
Former showrunner Scott M. Gimple, who now oversees the Walking Dead brand for AMC, debunked the coma theory ahead of the series' eighth season, which saw an older-looking Rick Grimes waking up in a sequence meant to mirror Rick waking up way back in th 2010 pilot.
The sequence was later revealed to be a hallucinatory flash forward into a possible future.
Series veteran Lennie James, who plays Morgan Jones, compared the idea to the infamous twist in classic soap opera Dallas that saw Patrick Duffy's Bobby Ewing show up alive and well after his apparent death, revealing the events were just a dream.
"In the trailer that we showed — there is a shot of Rick in a bed and he slightly looks different to the way that he normally does, and I did hear that lots of fans thought that that was Rick waking up out of the initial coma that he was in in episode 1, and that he was only now waking up out of it, and that the whole zombie apocalypse had just been a figment of his imagination," James said in October.
"That one was fun, and that would have been up there with ‘Bobby getting out of the shower’ in Dallas, but it’s not the case — but it was fun to find out about."
The Walking Dead returns Sunday, February 25 on AMC.