Colleagues of Bruce Willis say he had begun to feel confused and would ask people on movie sets why he was there.
The legendary actor, 67, this week announced his retirement through his family after being diagnosed with cognitive brain disorder aphasia.
And people who had been working closely with him over the last few years say there were sad signs that he was beginning to be affected by the disorder, which can leave people unable to process language.
It's said that after his diagnosis, it became common for directors to cut lines from his scripts and do their best to make sure he was never on set for more than one day at a time in order to accommodate him as best they could.
It's also been reported that the actor twice misfired a gun filled with blanks on the set of Hard Kill in 2020.
Speaking about how things had changed since the actor's diagnosis, his stunt double of 17 years, Stuart F Wilson, told The Sun : "We had seen some changes. Sometimes when you were talking to him he just seemed sidetracked. We would think it would mean nothing but you would wonder if there are other things going on."
Bruce's colleagues on White Elephant claimed the actor had become confused during the shoot, asking two crew members: "I know why you're here, and I know why you're here, but why am I here?"
Others said they were "relieved" to see him taking some time off and that the Die Hard star had recently been wearing a tiny hearing device so he could be fed his lines if he forgot them.
Director Mike Burns, who worked with Bruce on 2021's Out Of Death, said afterwards: "After we finished I said, 'I'm not going to do any other Bruce Willis movies'. I am relieved that he is taking time off."
Bruce's eldest daughter Rumer, 33, announced his retirement with a statement on Instagram this week, writing: " To Bruce’s amazing supporters, as a family we wanted to share that our beloved Bruce has been experiencing some health issues and has recently been diagnosed with aphasia, which is impacting his cognitive abilities.
"As a result of this and with much consideration Bruce is stepping away from the career that has meant so much to him.
"This is a really challenging time for our family and we are so appreciative of your continued love, compassion and support. We are moving through this as a strong family unit, and wanted to bring his fans in because we know how much he means to you, as you do to him.
"As Bruce always says, “Live it up” and together we plan to do just that. Love, Emma, Demi, Rumer, Scout, Tallulah, Mabel, & Evelyn"
It is not fully known what brought on Bruce's condition.
It's commonly caused by a stroke or a brain injury and affected around 350,000 people in the UK.
Game of Thrones star Emilia Clarke also experienced aphasia for a week after surgery to remove a blood clot.
It's been claimed Bruce was struck in the forehead by a projectile when a stunt went wrong 20 years ago.
The Mirror has contacted Bruce's representatives for comment.
