The Chelsea striker looks set to complete a return to the San Siro just 12 months after leaving the Italian giants for a fee of £97.5million.
Lukaku was a real fans' favourite in Milan thanks to his brilliant record of 64 goals in 95 appearances for the club, however that relationship was soured somewhat after forcing through a move to Thomas Tuchel's side last summer.
Just 12 months on, the Belgian attacker is expected to return to Italy.
In a statement, Ultra group Curva Nord said they will not boo and jeer the player when he runs out in an Inter jersey again.
But the message is clear that Lukaku will not be getting a hero's reception upon his return - instructing fellow fans not to 'drool' over him.
In a statement released on Instagram, they wrote: "Since Lukaku's return to Inter is very likely, some points need to be made clear: the Curva Nord supports Inter and will not make any objection to the player (despite last summer's behaviour).
"Given this, no one should go to welcome him with scarves or banners of the Curva or of the groups that compose it.
"Everything that in the future will eventually be done towards him will have to earn it on the field with humility and sweat.
"He was supported (and treated) like a king, now he is one like many."
They added: "Let us also be clear to everyone that we will never cheer against Lukaku if he wears the Inter shirt again.
"However, we invite all Inter fans not to fall into the opposite trap, that of running immediately and drooling after him.
"In addition to a clear instinctive emotional aspect, pretending that nothing has happened, would only give a further acceleration to that process that has been going on for years aimed at making us all stupid and supine consumers.
"Romelu Lukaku will return to Inter looking to replicate his impressive goal feats from his first two seasons with the Italian giants.
"We are not gentlemen at the mercy of the moves of players and clubs. We took note of Lukaku's betrayal and we were very upset. To a player these things can be forgiven over time, but they remain."