Logan Paul revealed his brother Jake was planning a stunt with Floyd Mayweather before he stole the ring legend's cap.
The younger Paul sibling was talking to Mayweather after he had faced off with Logan - before pinching his hat.
Mayweather reacted furiously and grabbed Jake in a headlock before aiming punches at the YouTube star.
The pound-for-pound great's security team jumped in and hauled their man away while Jake was left with a black eye.
And Logan, who will take on Mayweather in an exhibition bout on June 6, said: "I think its pretty f****** serious. I didn't expect Floyd Mayweather to try and kill my brother with all the security guards there."
He later added: "What the f*** just happened? I think that was a set-up I'm not going to lie, he had his boys get me before I could get involved.
"[Jake] told me he was going to do it and I told him not to.
"This s*** is so personal; this s*** was going to be kind of cute and we were going to put on a good show but now it's going to be a f****** fight, it's going to be a war.
"My brother has got a hat collection and I think he liked Floyd's hat and wanted to add it to his collection, it's nothing personal.
"Floyd looked pretty emotional, he can act cool all he likes on stage but I think my brother is doing my job for me."
And in a message to his opponent, he said: "We're going to get you your hat back and sorry on behalf of my brother."
Mayweather and Logan were due to clash in February but the fight was delayed due to the coronavirus pandemic.
It will now take place at the 65,000-capacity Hard Rock Stadium next month and be broadcast on pay-per-view.
The undercard will feature former world champion Badou Jack take on Jean Pascal in a rematch of a world title bout that saw Pascal win a controversial split decision in 2019.
Former unified light middleweight champion Jarrett Hurd is set to take on fellow American Luis Arias.
And to add to the celebrity element of the night, NFL legend Chad ‘Ochocinco’ Johnson is set to make his debut in what is described as an exhibition bout.