John Fury launched a bottle at KSI when the YouTube star started heckling his son Tommy Fury in a press conference.
With the two fighters set to meet in the ring on Saturday night at the Manchester Arena, Fury has been taking part in several interviews in the build-up.
But waiting for him at Wednesday’s open workout was his opponent, KSI, who did not waste time to start heckling him from a gantry above him.
And Tommy’s father, John, who is never afraid to take matters from zero to 100, launched a plastic bottle straight at the YouTube sensation.
It came just moments after he told his son to ‘stay calm’ as he initially sat next to him.
While John missed the target, KSI had to duck out of the way along with the rest of his entourage, sparking an argument which lasted a few minutes.
KSI could be heard shouting down: “Are you f****** disrespecting me?”
That wasn’t the end of the drama for Fury Sr as he later had to be restrained by bouncers as he looked to fight a man who appeared to be the father of Logan Paul, who is also fighting on the card.
The Fury and Paul families have established something of a feud after some of the derogatory comments thrown between both sides.
When Tommy took on Jake, the fight was dominated by trash talk before a punch was thrown.
Fury defeated Paul in Saudi Arabia in February and the 24-year-old is taking on another YouTuber this Saturday in KSI.
Meanwhile, Logan will be taking on Dillon Danis on the same night to settle personal beef.
The MMA fighter, who has been a member of Conor McGregor’s entourage, revved up the trash talk by involving the YouTuber’s fiancee Nina Agdel.
Due to the level of harassment, which included several mocked-up images of her of a sexual nature, Agdal was granted a temporary restraining order last month.
With both KSI and Paul fighting, the event has been billed as a double main event for the two Prime chiefs.