Johnny Knoxville reveals horrific injury that caused brain damage, forced him to quit Jackass stunts for life

Johnny Knoxville has revealed a stunt from his film Jackass Forever left him with brain damage, forcing him to end his career of putting his body on the line for entertainment. 

The upcoming flick will be the fourth feature-length installment of the iconic Jackass franchise, arriving over a decade on from 2010's Jackass 3D

Speaking to Howard Stern about a particular scene which involved Knoxville stepping into the ring with a bull, the now 50-year-old said the serious medical fallout from the incident was "tough to recover from". 

"I got a brain hemorrhage from that. So my cognitive abilities were in steep decline after that hit," he explained, as footage showed him being thrown high into the air by the animal. 

Knoxville suffered a concussion, a broken wrist and broken ribs. 

"I laugh now, at the time I was like 'oh no'. I had to undergo all these treatments, this transcranial magnetic stimulation - they buzz your head with these magnets for 30 minutes at a time - for like 10 -12 treatments over two months," he explained. 

"It's supposed to help with depression and help with my cognitive skills. It was a tough one to come back from - I was trying to edit the movie at the time, but I couldn't sit still." 

"No one in my family is happy with the stunts," he added. "The bull hit was the worst hit I've ever taken from a bull or maybe period. My cognitive abilities really declined." 

Knoxville said he knew going into the film that he would no longer be able to "put himself on the line" with stunts that could "forever change his life", but doctor's advice following his injury confirmed that. 

"This last concussion I did slip into a little bit of a depression - that hasn't happened before. I can't take any more hits to the head," he said. 

"I think I've done enough. I don't have anything to prove. I still have control of all my faculties. I don't need to do large stunts anymore." 

The father-of-three said his "brain was playing tricks on him" in the months after the incident, but therapy and going on antidepressant medication had "completely turned him around". 

"It was a really hard recovery from this last injury. But I'm great now, I feel like I'm the healthiest I've ever been," he said.