The PFA is deeply saddened by the devastating news that Ugo Ehiogu has passed away, aged just 44.
A statement made by Tottenham Hotspur said that Ugo died in hospital in the early hours of Friday.
Ehiogu, who was Spurs' Under-23s coach, was capped four times by England.
"It is with immense sadness that we announce the passing of Ugo Ehiogu, our Under-23 coach.
"Ugo received immediate treatment after suffering a cardiac arrest at the Training Centre yesterday before being transferred to hospital, where he passed away in the early hours of this morning.
Head of Coaching and Player Development John McDermott said: 'Words cannot express the shock and sadness that we all feel at the club. Ugo's immense presence will be irreplaceable. Our heartfelt sympathies go out to his wife Gemma and his family.'
Ehiogu made over 200 appearances for Aston Villa between 1991 and 2000 and then spent seven years at Middlesbrough.
He won the League Cup with Villa in 1994 and 1996 and won the same competition with Boro in 2004.
The England defender also played for West Bromwich Albion Leeds United, Glasgow Rangers and Sheffield United.
Following his playing career, Ugo moved into coaching and has been at Spurs for the last 3 years.
Aston Villa have announced they will hold a minute's applause before their Championship match against Birmingham City on Sunday, with both sets of players to wear black armbands.
PFA Chief Executive Gordon Taylor paid tribute to the former Aston Villa defender: “Ugo was a giant of a man, both in statue and quality.
“A wonderful player and a top-class coach who really cared about the game. He was humble with a wry sense of humour and was always great company.
"A most dedicated and influential member of the PFA's Black Coaches group and he toured the West Indies with the PFA's Legends team. He was a brilliant ambassador for the game.
“On behalf of all at the PFA, my most sincere condolences go to all his family, friends and former teammates. He will be sadly missed by all who knew him.”
Football pays tribute to Ugo Ehiogu:
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
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
Devastating news on the big man Ugo ehiogu you will be Sadly missed but never forgotten RIP big man.
— leehendrie77 (@leehendrie77) April 21, 2017
Ugo made four senior appearances for the #ThreeLions, scoring once.
— England (@England) April 21, 2017
He later coached our #YoungLions at 2013's Under-20 World Cup. pic.twitter.com/raoGmdyQ89
We will be holding a minute's applause before our derby with @BCFC...
— Aston Villa FC (@AVFCOfficial) April 21, 2017
Both sets of players will wear black armbands as a mark of respect. pic.twitter.com/yY2Gf2Dw51
Rangers Football Club is shocked and saddened by the sudden passing of former defender Ugo Ehiogu: https://t.co/PETGbYohOU pic.twitter.com/b5sqJP2DyR
— Rangers FC (@RangersFC) April 21, 2017
đź“· Where it all began...
— West Bromwich Albion (@WBA) April 21, 2017
Our earliest photo of a true gentleman of the game. Such sad news. RIP Ugo. pic.twitter.com/2KQBUpkunZ