Jake Paul mimicked Conor McGregor before losing his cool as he weighed in for his YouTube fight with AnEsonGib.
The social media rivals will clash over six rounds in Miami tonight as they make their professional boxing debuts.
And Paul, younger brother of Logan, faced off with Gib in a karate stance reminiscent of the one deployed by McGregor.
But the American's mask then slipped as he shoved his British rival before the pair were kept apart.
And fans were quick to criticise Paul with one tweeting, "Why is Jake Paul trying to be Connor McGregor... embarrassing."
Another added: "Please don’t try and pull the Conor McGregor pose off Jake Paul. You can’t fight, end of. Horrific."
Meanwhile, Deji, brother of KSI who lost to Logan last year, said: "Jake Paul is a Conor McGregor wannabe."
Jake later explained his reaction, claiming it was Gib who started the confrontation.
"It's an example of what's going to happen tomorrow night, I'm bringing the fight to him," he told Sky Sports.
"He tried to butt heads with me and I threw him across the stage; I showed him how a real push is done.
"He's in for a lot of energy tomorrow and a lot of aggression.
"It's a natural reaction, he tried to come into me and I was like, 'Get the f*** away from me'.
"I'm going for the KO and I think it's going to happen, he's got a big head."
Gib, however, believes he has taken his rival out of his comfort zone.
"I think madness is embedded into my DNA," he said.
"For him, when push comes to shove, he likes to have control in every situation of his life.
"This is a type of situation when he doesn't have control. He doesn't have control of his opponent, he won't be in control of the fight, so I think that type of pressure will eat him a little bit."
