Although he had been unwell for awhile, it was stated he had died of natural causes.
A tearful Bertie Auld, 78, his former team-mate and long-time friend, led the tributes to one of football’s biggest personalities.
He said: “I’m devastated, absolutely heartbroken.
“Tommy was one of my favourite people, a great colleague and a genuine pal.
“He enjoyed a laugh with the best of us. You never saw him down and he never complained even when things went against him.
“We knew he hadn’t been in the best of health for a while, but this is still a shock.
“I loved the guy and it was obvious the Celtic fans did, too.
“He was undoubtedly one of the greatest-ever Celtic players and the supporters recognised that.”
In March 2011, Mary, 64, broke off from a family holiday in Florida to return to Scotland after her husband had been taken to Stirling Royal Infirmary suffering from a stomach complaint and suffering the loss of feeling in his legs.
Doctors believed he may have been dehydrated.
He had been ill for around a week before his GP was called in and had him admitted to hospital.
The footballing icon made a full recovery from the mystery virus and was released after being kept in for a lengthy spell for observation.
The former Scotland international defender was back in hospital in August last year after injuring a hip in a fall.
He was found at his home in Dunblane before being taken to Forth Valley Royal Hospital.
At the time, wife Mary said: “Tommy got a scare after a simple accident at home.
“He lost his footing getting out of a chair and toppled against a coffee table.
“We’ll have to wait and see how serious it is but we know he is in the best hands.”
Gemmell, who suffered from Type 2 diabetes, had been plagued by health problems and had been hospitalised three years ago after becoming ill at home.
He is the fourth Lisbon Lion to pass away, following Bobby Murdoch, Ronnie Simpson and Jimmy Johnstone.
The club will celebrate the 50th anniversary of their most famous triumph, the European Cup victory over Inter Milan in the Portuguese capital in 1967, on May 25.