Production on the upcoming eighth season of AMC's zombie drama was halted earlier this week after Bernecker was injured during rehearsal for a stunt and later hospitalised.
He reportedly fell off a 25-foot balcony onto a concrete floor and was transported to a nearby hospital in Atlanta, where he was being treated in the intensive care unit. He was later pronounced brain-dead and taken off the ventilator, the medical examiner told TMZ, which was first to report the news.
"We are saddened to report that John Bernecker, a talented stuntman for 'The Walking Dead' and numerous other television shows and films, suffered serious injuries from a tragic accident on set," AMC said in a statement at the time, according to Deadline. "He was immediately transported to an Atlanta hospital, and we have temporarily shut down production. We are keeping John and his family in our thoughts and prayers."
Fellow stuntwoman and Bernecker's girlfriend, Jennifer Cocker, shared a heartbreaking update on Facebook Wednesday, suggesting that he was unresponsive.
"John deserves to be seen by every neurosurgeon and doctor there is until one of them sees the life we all know he has in him and bring him back to us... THIS ISNT FAIR."
"Walking Dead" star Lauren Cohan also tweeted about the accident, asking the fan community to keep Bernecker and his family "in your prayers today."
In addition to his work with "The Walking Dead," Bernecker has performed stunts for TV series like "24:Legacy," "Scream Queens" and "Into the Badlands," as well as major motion pictures including "The Hunger Games," "The Fate of the Furious," and Marvel's upcoming "Black Panther."
"The Walking Dead" was set to return this October on AMC.