Morgan plays Negan while Burton played Negan's wife, Lucille, on season 10 of "TWD."
Gus Morgan played the young walker reaching inside the wall of Alexandria that was biting at the teens.
"I personally just pretended that the people I tried to nip at were tacos because my determination for tacos is very strong," said Gus Morgan on an interview segment of after-show "Talking Dead."
"He was six when Jeff started doing this show, so his whole childhood has been this show so for them to include him in the last year is just really nice," Burton shared on last week's "Talking Dead," when she revealed his cameo.
"Mom, I found myself," Burton said of when Gus came home from set. "He knows what he wants to do now."
Gus Morgan said he was wearing pajamas while he was shooting, something that was part of the backstory that they came up with for his walker.