Anthony Joshua and Jarrell Miller exchanged insults as they came face-to-face in an angry press conference in New York ahead of their world heavyweight title clash.
The pair will clash for Joshua's WBA 'super' and IBF titles at Madison Square Garden on June 1 after projected negotiations with the likes of Tyson Fury and Deontay Wilder fell through.
Brooklyn-born Miller, whose unbeaten 24-fight record boasts few recognisable names, appeared to anger Joshua by shoving his chest during their initial head-to-head.
From that moment the pair were kept apart on the press conference stage, with a serious-looking Joshua content to let challenger Miller do most of the talking.
Miller said: "You've got no idea - I breathe and eat and sleep Anthony Joshua.
"I've got a picture of him of my screensaver, I've got a picture of him on my wall. I wake up in the morning and I think about Anthony Joshua.
"This is bigger than boxing, bigger than belts, bigger than me. I'm playing by nobody's rules and the sooner you understand that you get to know the kind of man I am."
Joshua's attempt to land a further unification bout has been frustrated since he won his last bout against Alexander Povetkin by seventh-round stoppage in September.
With Fury and Wilder eyeing a rematch - and the situation further complicated by the fact all three major players in the division are now contracted to rival US networks - Miller, despite his average-looking record, was the next best in line.
Joshua appeared to struggle to summon the enthusiasm for his latest title defence, giving short shrift to the handful of questions from the floor and mocking Miller's credentials for the fight.
Joshua said: "I'm going to take it seriously but he isn't as smart as me and I'll knock him out, 100 per cent. He punches like a fairy - he's the softest puncher in the heavyweight division."