Rumours spiralled in the aftermath of Joshua’s shock defeat to the Mexican-American in June, including the lingering effects of sparring contributing to the upset.
But Hearn has laughed off suggestions Joshua has encountered trouble this time around.
“It (the story) said, ‘Joshua hurt in camp,’ it’s not even worth answering. But the truth is he’s had a great camp,” Hearn told Behind The Gloves.
“He’s much more focused than last time. He’s sparred really well.
“The difference in this camp is that his sparring has been world, world class.
“He’s had top, top guys. Andrew Tabiti, Tyrone Spong, Bryant Jennings, Dereck Chisora. Top sparring, which has put pressure on him.
“He hasn’t been hurt, he hasn’t been ill, he’s good to go.”