Former England and Premier League defender Ugo Ehiogu has died aged 44 after a cardiac arrest, Tottenham Hotspur confirmed on Friday.
Ehiogu, who had been working as Tottenham's under-23 coach, was rushed to hospital after collapsing at the club's training ground on Thursday and died in the early hours of Friday.
"It is with immense sadness that we announce the passing of Ugo Ehiogu, our under-23 coach," a Tottenham statement read.
In wake of the shock death, a final tweet from Ehiogu promoting kindness has gone viral.
On March 29, Ehiogu tweeted: "Gave a homeless girl PS10 last night in Dalston.She didn't ask or beg.Random impulsive act from me. Not gona lie. Felt good. #dosomethingkind."
As a result, people from across the world have promoted the #dosomethingkind hashtag - which was trending in Great Britain and the United States - with some donating 10 pounds ($A17) to charities in memory of Ehiogu.
User Tom B (@tom_anyname) tweeted: "Just donated PS10 to each of @ShelterCymru &@TheBHF via random London marathon runners in memory of Ugo #dosomethingkind."
Former Premier League footballer Paul Dickov (@OfficialPDickov) tweeted: "Sums the man up #gentleman #dosomethingkind AdegreesAYA'ATM."
"Words cannot express the shock and sadness that we all feel at the club," said John McDermott, Tottenham's head of coaching and player development.
"Ugo's immense presence will be irreplaceable. Our heartfelt sympathies go out to his wife Gemma and his family."
It is with immense sadness that we announce the passing of Ugo Ehiogu, our Under-23 coach. pic.twitter.com/sSU0yqVfyk— Tottenham Hotspur (@SpursOfficial) April 21, 2017
The Football Association has led the tributes to Ehiogu, with England manager Gareth Southgate having played with Ehiogu for both Villa and Boro.
The tribute on the official England Twitter account read: "We're devastated to hear the news that Ugo Ehiogu has passed away. Our thoughts and sympathies are with all lucky enough to know him."
Villa released a statement expressing their deep sadness "to hear of the death of our former defender Ugo Ehiogu. Our thoughts are with his family at this terribly sad time."
The club added that there would be a minute's applause ahead of their derby with Birmingham, with the teams wearing black armbands.
Lee Hendrie played with Ehiogu at Villa Park and with Sheffield United and told Sky Sports: "This is an absolute shock, to think this could happen to a man of his fitness and age. It is devastating, crazy."
Boro said they were "deeply saddened to learn of the tragic passing" and Australian goalkeeper Mark Schwarzer, who played with Ehiogu at the Riverside, told BBC Radio 5 Live: "He loved the game and he was really respected at Tottenham. It was a pleasure to play with him."
A commanding centre-back, Ehiogu began his career at West Brom but made his name with Aston Villa, for whom he made 237 appearances over 10 seasons.
He also played eight seasons for Middlesbrough and had brief spells with Rangers and Sheffield United.
Ehiogu played four times for England, scoring once. After calling time on his playing career in 2009, Ehiogu began coaching and joined Spurs' coaching staff in 2014.
RIP Ugo Ehiogu..tremendous player..and even better man..words can't do justice how sad I am.xmb— Mark Bosnich (@TheRealBozza) April 21, 2017
Can't believe the news that Ugo Ehiogu has passed away. Calm & warming vibe when in his company. My heart goes out to his family! #RIPUgo— Rio Ferdinand (@rioferdy5) April 21, 2017
We're devastated to hear the news that Ugo Ehiogu has passed away.— England (@England) April 21, 2017
Our thoughts and sympathies are with all lucky enough to know him. pic.twitter.com/UXT4CXNIne