Wilder made Joshua an offer of $50 million (£35.9m) to fight before the end of the year, but due to not being told the full details of the deal, it was declined by the Brit and his team.

However, Joshua's promoter Hearn has insisted there is still ongoing communication and that he remains hopeful the fight can get made.

"70 percent," Hearn told Sky Sports when asked the likelihood of the fight happening. "Their side has been very vocal in letting the media know about everything that is happening.

"We've had some positive conversations over the past day or so.

"Negotiations are ongoing and we're all hopeful to reach an agreement."

Despite the public desire for a four-belt unification clash between Joshua and Wilder, Hearn has named WBA mandatory challenger Alexander Povetkin as well as Jarrell Miller as potential other opponents for the Watford boxer if the bout doesn't materialise.

"Povetkin is the guy we have to fight next," Hearn added. "If we fight Wilder, Povetkin will wait.

"Would we apply for a voluntary? Maybe. Would the WBA allow it? Maybe. But, really, it is Wilder or Povetkin.

"We are talking to Miller, but mainly we are talking to Povetkin because he is the guy we'll have to fight if we don't fight Wilder."

Joshua's last outing was a unanimous points victory over New Zealand heavyweight Joseph Parker on March 31.