Tyson Fury and Deontay Wilder had to be separated at the press conference to promote their WBC heavyweight title fight at the Staples Centre in Los Angeles on December 1.
Fury had already dismissed suggestions he was the "challenger" to the champion, from America, before getting out of his seat and demanding Wilder join him for a "body spar".
"I am no challenger for no man. I'm the linear heavyweight champion of the world, the best of the best," Fury had said.
"This is two champions colliding, equal rights, rephrase and start again."
A similar exchange had taken place between Fury and Wladimir Klitschko before they fought in 2015, when the challenger's anger suggested he felt under intense pressure.
He later produced an impressive composed performance to secure one of the biggest shocks of the modern era in securing victory.