Anthony Joshua and Wladimir Klitschko set for December world title fight in Manchester

He has revealed, however, a concern it is not the "right fight" for Joshua to be taking.

Press Association Sport understands an announcement will be made in the coming days to confirm the IBF heavyweight champion is making the second defence of his title against Klitschko at the Manchester Arena on December 10.

Former IBF, WBO and WBA champion Klitschko would represent the most difficult fight of his short professional career, and a significantly greater challenge than any other previous opponent.

There remains a risk Joshua could lose his undefeated status and title to a heavyweight considered among the finest in history and that Matchroom's Hearn will be accused of making the fight too soon. The promoter is instead aware that is the chance they are taking.

"Terms are virtually there between the two now, there are plenty of things that have got to fall into place," the 37-year-old told BBC Radio 5 Live. "Tyson Fury's vacated the (WBA and WBO) belts; the governing bodies would love Anthony Joshua v Wladimir Klitschko to have the belt on the line.

"I don't think it is the right fight for Anthony Joshua, but isn't that what's exciting about it? You can't really win as a promoter because on one hand people are saying 'You're putting him in too easy (past) fights', and then they're saying 'That's a bit early for him isn't it? What are you doing?'.

"It's a complete 50-50 fight. Freshness, sharpness leads you to Anthony Joshua, and then the experience says Anthony hasn't got a chance. It's definitely a jump too early, it's his 17th pro fight, he's never been in with anyone like Wladimir Klitschko, anyone with his experience.

"But I also believe Wladimir Klitschko has never been in with anyone like Anthony Joshua."

There had been concerns Joshua's television deal with American network Showtime, and Klitschko's with rivals HBO, may prove too big a problem to overcome.

Similar circumstances had contributed to delaying the fights that eventually took place between Manny Pacquiao and Floyd Mayweather and Mike Tyson and Lennox Lewis, but Hearn explained: "It's a case of going through the sanctioning requests. The deal between the fighters: that's there. The financial terms are agreed.

"We had a problem with US broadcasters because they're both with different networks: that's sorted out. It's a case of getting the paperwork in order, the sanctioning in order.

"Hopefully in a couple of days we'll have an announcement.

"It looks like Manchester. It's a huge event."