Barbara Windsor's husband Scott Mitchell has said the actress does not recognise him sometimes, saying "it's like a body blow".
The former EastEnders and Carry On star has been living with Alzheimer's disease in 2014, and Mitchell spoke publicly about her diagnosis for the first time last year.
Speaking on Good Morning Britain on Thursday, Mitchell said Windsor becomes upset when she realises what has happened.
"It hits her at different times," Mitchell said. "Most of the time she knows me," he continued, but added: "She can just look at me, straight in the eye, and say 'Do you know where my husband Scott is?'
"They're really tough things. It doesn't matter how used to it you get in a way. Each time it happens it's like a body blow.
"Then she realises it and then she's a bit upset with herself that it's happened.
"So there is that sense of isolation for the person as well. They also sense that life is going on and they're not a part of it like they used to be."
Mitchell added: "Obviously the confusion is very unsettling for her.
"She's still got that lovely sense of fun within her. She still loves to sit there and giggle. I make her laugh, she makes me laugh."
Windsor made a rare TV appearance on the show to wish viewers a happy Christmas along with her husband.
Dame Barbara Windsor sends you a very special message. 🎁
— Good Morning Britain (@GMB) December 12, 2019
Whether it's #bereavement, separation, #dementia, ill-health or #disability, you can help end #loneliness by pledging some time with GMB's #1MillionMinutes.
👉https://t.co/vdzTe6aSGq pic.twitter.com/pidTb7aZ9q
82-year-old Windsor, famous for her roles in nine Carry On films and for playing pub landlord Peggy Mitchell in EastEnders, was given the heartbreaking diagnosis on April 22, 2014.
