The news was announced on Sunday just two days after his former teammate and World Cup winner Nobby Stiles passed away at the age of 78. He too had been suffering from dementia as well as prostate cancer.
Charltons older brother Jackie also died earlier this year suffering from the illness.
In fact, Charlton the younger is the fifth member of the England World Cup winning team to be diagnosed with the disease -apart from his brother and Stiles, both Ray Wilson and Martin Peters also contracted it. They did kin 2018 and last year, respectively.
Charltons wife Lady Norma Charlton has said that the family chose to make the news of her husbands condition public so that it could help others.
Already campaigners are linking it to research that shows the greatly increased risk to footballers of dementia compared to the general population.
A 2019 Glasgow University study found the incidence of professional footballers dying as a result of dementia is three and a half times higher than average.
The issue first came to the fore in Britain following the death in 2002 of former England and West Bromwich Albion footballer Jeff Astle at the age of just 59. A subsequent inquest found that he had died due to significant repeated head trauma, the consequence of heading heavy footballs during his professional career.
Whilst balls are now lighter than during Astles and Charltons playing career, and less likely to absorb moisture, there is still an increased danger to players general health involved in heading them every day.
That is one reason why in the UK, the Football Association have issued new guidelines restricting the amount of heading in under-18 football.
Some countries have gone further, and it is completely banned in youth football in the USA.
Charlton is still a director at Manchester United, the club for whom he made more than 750 appearances, having been one of the survivors amongst the Busby Babes from the Munich air crash in 1958 which claimed the lives of many of his teammates at the time.