Mario Balotelli was caught smoking in the toilet on a train during AC Milan's journey to face Fiorentina and will be fined, the club's chief executive, Adriano Galliani, said on Sunday.
Balotelli was reprimanded by the train guard, who allegedly told Galliani: "You need to pull his ears. He was smoking in the bathroom," Gazzetta dello Sport reported.
"I want to say that we're going to fine him," Galliani said. Smoking is banned on Italian trains.
Balotelli has scored seven goals in eight appearances since joining in January from Manchester City, where he proved to be an irascible nuisance for coach Roberto Mancini.
Milan squandered a two-goal lead against 10-man Fiorentina to draw 2-2 on Sunday after conceding two penalties. Predictably, Balotelli threw a tantrum towards the game's conclusion after he was involved in an altercation with Fiorentina's goalkeeper, Emiliano Viviano.
He stormed into the tunnel gesticulating angrily, having fortuitously avoided a red card for a late challenge on one-time City teammate David Pizarro.