Lazio security chiefs have urged their fans not to give fascist salutes tonight at Parkhead and ruin the international image of the club.
The Italian side is on a final warning from UEFA after 20 of their fans made the gesture during their last game in the Europa League against French side Rennes.
It's led to the Curva Nord section of their Stadio Olimpico to be closed when Celtic visit Rome next month, although the club is appealing the sentence.
Tomorrow they will have 1,500 fans in Glasgow, which reportedly includes 300 "ultras". The club has taken the security side of things so seriously, they have employed specialist crime cops to accompany their fans to Scotland.
Now Lazio security manager, Nicolo D'Angelo, has urged supporters to behave in Glasgow.
He said: "We have given lots of information to our supporters. We couldn't be more clear.
"Unfortunately, we still have a minority of fans who believe it's acceptable to give the Roman Salute and to make rascist comments.
"This is unacceptable and no longer tolerable. We want there to be a healthy relationship with the fans, not this relationship, which has been spoiled for so many years.
"We have repeatedly told them we have zero tolerance for this behaviour. The image of Lazio abroad is very important to us. It counts a lot to us. Our credibility is on the line.
"When UEFA punish us, they are punishing our thousands of well behaved fans."
And D'Angelo explained why they are appealing their partial stadium closure ban from UEFA.
He said: "We will present a constructive appeal to UEFA. We want to show them how the club have worked with society and police to identify those who have discredited us.
"Anti-social behaviour has been eliminated with our code of ethics. We want our supporters to respect the rules."