The club announced on their Twitter feed: "Celtic legend Sean Fallon has died peacefully at the age of 90. Our thoughts and prayers are with his family."

The Irishman unfurled the Scottish Premier League flag before the champions began the defence of their title at Celtic Park in August last year.

Celtic said Fallon died peacefully this morning surrounded by his family.

Fallon, who made his Celtic debut in 1950, was credited with bringing the likes of Tommy Gemmell, Danny McGrain, Kenny Dalglish, Davie Hay, Lou Macari and Pat Bonner to the club.

Chief executive Peter Lawwell told the club's official website: "Sean Fallon was a Celtic legend who devoted much of his life to the club he loved.

"He was, of course, a supporter, first and foremost, and he was proud to have worn the green and white hoops that he loved.

"He did so with fearless distinction over eight years in the 1950s, and Sean was at the heart of all of our triumphs, including that famous 7-1 League Cup victory in 1957.

"Ten years later, he was part of our greatest ever success, winning the European Cup in Lisbon.

"Working alongside Jock Stein, Sean helped to deliver that trophy, along with nine consecutive league titles and numerous other trophies.

"He was an integral part of the club's success, and also played a vital role in identifying talented young players who would go on to become great Celts.

"He was a gentleman with a great sense of humour, and always a welcome guest here at Celtic Park. And there could have been no more fitting person to unveil the championship flag at this start of this, our 125th anniversary season, than a man who gave so much to Celtic Football Club.

"Sean will be sadly missed but he will never be forgotten for what he did for our club."

Manager Neil Lennon added: "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."