Ex-Nigeria international Justice Christopher has died aged 40.
The retired midfielder played for Nigeria at the World Cup in 2002, facing Sven-Goran Eriksson's England in the group stage.
Christopher passed away on Wednesday morning at his hotel in Jos, Nigeria. He reportedly played a a social game of football just 24 hours earlier.
No official cause of death has been disclosed. An autopsy is expected to be carried out this week.
"We are devastated to hear of the sudden passing away of former Super Eagles midfielder Justice Christopher early on Wednesday morning," confirmed a statement from the Nigerian Football Federation.
"Our thoughts and prayers are with his family and football community in Nigeria. May his soul rest in peace."
Christopher played for several clubs in Nigeria and Europe - representing Belgian outfit Antwerp, Bulgarian side Levski Sofia and clubs in Sweden, Denmark and Russia.
He picked up 11 senior caps for Nigeria, playing in all three of their 2002 World Cup games. He also captained his country's U20 team.
Christopher started and finished the World Cup clash against England in 2002, helping Nigeria keep a clean sheet against one of the favourites for the tournament.
England's team that day included David Seaman, Rio Ferdinand, Sol Campbell, Ashley Cole, David Beckham, Paul Scholes and Michael Owen.
Christopher was praised by the media for his performance against Sweden at that tournament, which was held in South Korea and Japan.
Nigeria narrowly lost the game 2-1 to be eliminated from the World Cup.
"Equally adept as both a defender and midfielder, Christopher only came to the fore in this season's African Nations Cup in Mali," described a BBC profile of Christopher ahead of the tournament.
"He impressed the coaching staff and looks on course to make it to more than just this year's World Cup.
"His role in qualifying was consigned to just two appearances but his speed and vision will be a major boost as the tournament drags on."
Christopher retired from football at the end of the 2006-07 campaign - aged just 25 - but made a brief comeback for Nigerian club Nasarawa United in 2012.
The midfielder's promising career was plagued by a knee complaint, restricting him to just a handful of appearances at club level.
Former Everton defender and close friend Joseph Yobo has paid tribute to Christoper.
"My family and I are deeply saddened by the awful news that my close friend Christopher has passed away," said Yobo, who is Nigeria's assistant manager.
"Thoughts and prayers go out to his family.
"A very gentle man that we shared some wonderful memories with throughout our international career. He will be missed by so many people and I honestly can't get over the shock."
The Confederation of African Football (CAF) tweeted: "Saddened to hear the loss of former Nigeria star Justice Christopher. Our thoughts and prayers are with his family and friends."
