Speaking in this month's issue of Four Four Two magazine, former Barcelona star Deco has admitted that Celtic fans are the best in the world.
Deco, now 37, has retired from professional football but had an illustrious career, which was kick started by Jose Mourinho at Porto.
The Brazilian-born Portugal international was a key player under Mourinho, helping Porto win the 2004 Champions League trophy against all the odds.
Whilst Deco went on to become a hero at Barcelona and finished his career with Chelsea and then Fluminense, he has recalled one striking moment of his time in football.
One year before winning the Champions League, Porto secured the UEFA Cup trophy with a dramatic 3-2 win over Celtic in extra time.
A topsy-turvy clash in Seville ended with Mourinho and his Porto side winning the UEFA Cup, with Deco playing a key role as the chief playmaker of the team.
Now, speaking to Four Four Two, Deco says that the UEFA Cup Final showed him that Celtic have the best fans in the world after an incredible night in Seville.
"Celtic fans are the best in the world," said Deco. "There were 2,000 of them outside the 2003 UEFA Cup Final in Seville without tickets, while inside the atmosphere was incredible. That was one of the best finals I ever played in," he added.
This is a sentiment echoed by his former Barcelona team-mate Lionel Messi, who recently told the Celtic official website that the Bhoys have the best atmosphere in Europe - and hopefully, Celtic will be returning to the Champions League group stage next season.