The 33-year-old MMA fighter allegedly got ticked off at the 31-year-old rapper because of a denied photo request with Megan Fox.
Conor reportedly wanted to snap a quick pic with the actress, and Machine Gun Kelly did not want his girlfriend to pose with him.
McGregor is clearly the type of millionaire who doesn't mind causing a scene if he's in the mood... and his mood was allegedly red hot!
Videos of the scene reveal that Conor seemingly tried to strike the singer and throw a drink at him. Megan was quickly ushered away by security, who stepped in to sepperate the stars.
Megan's dress was headline-worthy all by itself, and the photographers were reportedly mad at Conor for jeopardizing their opportunity to snap pics of her see-through gown.
“They scuffled then it settled down and Conor went for him again,” a source told PageSix. “[The photogs] were going to boycott Conor because they were worried MGK and Megan wouldn’t walk.”
Another source told the outlet that "security was having trouble holding [Conor] back." Check out pictures and videos at TheBlast.com.