Gerry Anderson, creator of the Thunderbirds and Joe 90 puppet superhero TV shows, has died, his son announced.
Mr Anderson was 83 and had been suffering from Alzheimer's Disease since early 2010.
His condition had deteriorated in the past six months and he died peacefully in his sleep today, Jamie Anderson said.
"I'm very sad to announce the death of my father, Thunderbirds creator, Gerry Anderson," Jamie wrote on his website.
"He died peacefully in his sleep at midday today having suffered with mixed dementia for the past few years."
Mr Anderson also created the hit TV shows Captain Scarlet and Stingray.
He is survived by his wife and four children.
Having been diagnosed with mixed dementia at the age of 81, he and his son Jamie became active supporters of Alzheimer's Society, recently taking part in the Society's flagship fundraiser Memory Walk.
Jeremy Hughes, chief executive at Alzheimer's Society, said: "Gerry Anderson has been an outstanding supporter of Alzheimer's Society and campaigner on behalf of people with dementia.
"He was determined, despite his own recent diagnosis, to spend the last year of his life speaking out for others living with dementia to ensure their voices were heard and their lives improved."