The sudden death of former Northern Ireland football captain Alan McDonald at the age of 48 is devastating news, a close friend from the sport said.
Sammy McIlroy said he was stunned to hear of the loss of his former team mate.
The QPR stalwart won 52 caps for his country and was a member of Northern Ireland's World Cup side in 1986.
McDonald went on to manage Glentoran, winning the Irish League title in 2009, and also coached his country's under-21 side.
An Irish Football Association spokesman said: "We are deeply shocked at the death of Alan, who won over 50 caps for Northern Ireland. To die at such a young age is terrible."
Former Northern Ireland manager Sammy McIlroy, a close friend and former team-mate of McDonald's, said: "I'm shell-shocked. Words can't even enter my head at the moment.
"Forty-eight is so young. Alan was always larger than life - during his career and after. I've just spoken to Norman Whiteside and he is devastated."
The Belfast-born footballer was said to have died suddenly while playing golf. A short statement was also posted on the IFA's official website: "The Irish FA is saddened by this morning's news of the sudden death of Alan McDonald. Our thoughts are with his family at this time."
The Lord Mayor of Belfast expressed his deep regret at news of the tragedy.
Alderman Gavin Robinson said: "Alan was a much respected sportsman who excelled on the football pitch and went on to captain the Northern Ireland team. On behalf of the citizens of Belfast, I extend our deepest sympathy to his family at this difficult time."