Joshua vs Ruiz Jr: AJ ready to erupt when he returns to ring, says Eddie Hearn

Andy Ruiz Jr firmly believes he can dethrone Anthony Joshua, but Britain's unified champion is "ready to erupt" on his US debut, says promoter Eddie Hearn.

Ruiz Jr will face the WBA 'Super', IBF and WBO heavyweight champion at Madison Square Garden on June 1, live on Sky Sports Box Office, after Joshua's original opponent Jarrell Miller failed a drug test.

"I'm just glad that AJ and the people who know boxing, know how difficult a fight this is because when you look at the guy, you think it's going to be easy work for Anthony Joshua," Hearn told Sky Sports.

"So a lot of people have thought 'this guy's not in Joshua's shape' - he's not. But what he does have is tremendous boxing IQ, fast hands, good work rate and he's not afraid to let his hands go. He's one of the reasons I wanted to choose him because I know him, I know what he's all about.

"Look at his response today, and look at the response from people in boxing - they say this is a much tougher fight than Jarrell Miller because he has much faster hands, he likes to move inside, he has a great amateur pedigree as well, and this is a massive banana skin.

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"AJ doesn't really have a lot to gain, because the outsiders are saying 'he'll win that fight easy', but talk to people around here and you'll get the reaction from them today. They know this is a real, real, tough, tough fight.

"Andy Ruiz has a chance to make history and become the first-ever [Mexican] world heavyweight champion. Mexico is behind Ruiz and he believes he's going to do it. He really believes he'll beat Joshua.

"With everything that's happened, AJ is ready to erupt at Madison Square Garden. He can't wait to make his American debut. It's going to be an amazing week. We've got the most unbelievable activities planned around the fight.

"It's going to be a huge moment for his career. He's just got to be on it and focused, because Ruiz is going to be a little pitbull in the ring at Madison Square Garden."

Watch Anthony Joshua against Andy Ruiz Jr and Katie Taylor's undisputed world lightweight title fight versus Delfine Persoon at Madison Square Garden in New York on June 1, live on Sky Sports Box Office.