Manchester United and Scotland great Denis Law has been diagnosed with dementia.
The 81-year-old says he has "'mixed dementia', which is more than one type of dementia, in my case, this being Alzheimer's and Vascular dementia".
Law is not alone in battling the condition, with the Football Association supporting two ongoing research studies examining ex-professionals for early signs of neurocognitive degeneration.
England World Cup winners Nobby Stiles, Jack Charlton, Ray Wilson and Martin Peters are among those to have died from the disease.
Here the PA news agency takes a look at some of the former players known to be battling dementia.
Jimmy Calderwood, 66
In August 2017 former Aberdeen boss Calderwood, who guided the club to the last 32 of the UEFA Cup and a Scottish Cup final, announced he was being treated for early onset dementia. His son Scott told the Aberdeen Press & Journal last year that his father was "OK just now" and "coping" with his condition.
Sir Bobby Charlton, 83
Another World Cup winner with England, the Manchester United stalwart is one of England's greatest ever players. His diagnosis was made public in November last year with his wife, Lady Norma, saying she hoped the information would raise awareness of the condition and help others who are suffering with it.
Gordon Cowans, 62
Cowans, a European Cup winner who made more than 400 appearances for Aston Villa across two spells with the club, was diagnosed with early onset dementia in March last year. Cowans told the Daily Mail in November that while the condition had only had a limited impact on him until that point, he knew "what is coming" having seen his friend and former team-mate Chris Nicholl battle against it.
Chris Nicholl, 74
Former Northern Ireland international Nicholl won two League Cups with Aston Villa, captaining the side in the mid-1970s, before playing more than 200 games for Southampton between 1977 and 1983. He later moved into management with the south-coast club and then Walsall, before a stint as assistant manager in the late 1990s with Northern Ireland, under the man who signed him for Saints – Lawrie McMenemy. Last summer fans raised money to replace a vital tracker watch for Nicholl after his was stolen.
Gordon McQueen, 69
McQueen's family said they were making his diagnosis, first made in January, public in order to raise awareness of the condition. McQueen played 30 times for Scotland and won the English First Division with Leeds and FA Cup at Manchester United.
Jimmy Millar, 86
The family of former Rangers striker Jimmy Millar went public with his diagnosis in May 2017, by which point he had already been suffering with it for a decade. Millar scored 162 goals for the Ibrox club, forming a famous partnership with Ralph Brand.
Jimmy Robson, 82
Seven members of Burnley's First Division-winning side from 1960 were diagnosed with dementia and six – including Ray Pointer and Jimmy McIlroy – have since died with the condition. Former target man Robson continues to fight it, with his daughter Dany campaigning for more to be done.
Dave Watson, 74
Watson, capped 65 times by England, was a member of Sunderland's FA Cup-winning side of 1973 and later lifted the League Cup with Manchester City. In February 2020 his wife Penny revealed he had been diagnosed with a neurodegenerative disease which his consultant believed to be chronic traumatic encephalopathy (CTE) – the condition which killed Jeff Astle in 2002.