Celtic legend Sean Fallon has died at the age of 90.
The news was confirmed on the club's Twitter feed on Friday morning.
A short statement read: "Celtic legend Sean Fallon has died peacefully at the age of 90. Our thoughts and prayers are with his family."
Fallon appeared 254 times for the Glasgow club between 1950-58 and was assistant manager to Jock Stein when the Hoops won the European Cup in 1967.
The Irish full-back was a fan favourite thanks to his work ethic and leadership.
After his playing career ended, Fallon became Celtic's assistant manager between 1962-1975 and then coached Dumbarton in the 1980-81 season.
Of his time with Celtic, he once said: "I was just an ordinary player with only a big heart and a fighting spirit.
"I can never find words to express my feelings at becoming a member of Celtic Football Club."
A tribute to Fallon on the team's website read: "He is a true Celtic great, having served the club faithfully and then as an integral part of the management team.
"Sean Fallon was, is and always will be a true Celtic legend. The thoughts and prayers of all at Celtic Football Club are with Sean's family at this sad time."
Celtic manager Neil Lennon said: "We are all shocked and saddened to hear of Sean’s death, and the thoughts of all the players and management are with his family.
"Sean was a great Celtic man, and it’s been a privilege to meet him over the years. He was always a very humble man when you met him, even though his achievements in the game were extraordinary.
"He did everything you could ever wish to achieve in football, as a player for both club and country, while he went to even greater things in management alongside Jock Stein. For these things, the Celtic supporters have always loved Sean and recognised him as one of our own because it was always his great love of Celtic which shone through.
"It was a fitting tribute that Sean unveiled the championship flag back in August and the welcome he received from the supporters spoke volumes. We will all miss him."
Fallon is survived by wife Myra and children Marie-Therese, Louise, Collette, Siobhan, Sean and Sinead.