John Middleton "couldn\'t walk away from" the issues people living with dementia face after leaving \'Emmerdale\'.
The 66-year-old actor departed the soap in 2017 when his character Ashley Thomas was killed off following a battle with the disease, and he has carried on raising awareness about dementia, most recently by opening the Alzheimer\'s Society\'s Memory Walk at York Knavesmire.
Speaking to the crowd, he said: "Going into that \'Emmerdale\' storyline made me realise the issues that people living with dementia face. It\'s a huge, huge issue.
"Having walked into it, I can\'t walk away from it, so I\'m doing this walk today."
John\'s commitment to the cause comes after he admitted last year he had stopped watching the ITV soap as soon as Ashley was killed off to "shut the door" on that chapter of his career.
The actor - who appeared on the programme from 1996 to 2017 - said: "I don\'t watch it I\'m afraid. It\'s not because I don\'t think its good, I think it\'s absolutely terrific and everyone else thinks that as much as me.
"But I had to shut the door on that and put it behind me and move onto the next thing.
"It needed to be as abrupt as that, really.
"Just for my own peace of mind, getting my head round the fact that this is a new start to my career and a very exciting one."
But he meets up with a number of his former co-stars, and is constantly reminded about Ashley\'s dementia storyline on a daily basis by fans.
He added: "I say I\'ve stopped watching the show, but still see old friends.
"Hardly a day goes by when someone doesn\'t stop me in the street and say, \'Thank you so much for telling my story,\' and then they tell me theirs.
"It\'s the biggest health concern we have, the story itself had extraordinary relevance."
