Joshua, 32, immediately exercised his rematch clause in his contract after being comfortably outclassed by Usyk at the Tottenham Hotspur Stadium in September.
The Ukrainian proved to be a class above the Watford ace as he shocked the world by beating the British rival in his own backyard much to his dismay.
And now Hearn has revealed former WBA, IBF and WBO champ Joshua will most likely fight newly crowned king Usyk in the spring but the fight venue is still being considered.
Promoter Hearn told Kugan Cassius of iFL TV: “Honestly not much other than we have to get together and decide a date.
“April is realistic for that fight and [as for] where it’s going to be, we’ve had offers from around the world, I think the UK will stage that fight, but we have to sit down with Alex Krassyuk.
“We’ll get Christmas out of the way and we’ll start moving forward with that because it’s time to start planning for that.”
And the promoter – who previously admitted it would take approximately £40million for AJ to let Usyk fight Tyson Fury before him – said ‘that looks very likely now’ after Joshua’s stablemate Dillian Whyte was declared the mandatory challenger to WBC king Fury.
He added: “Obviously, there were a couple of discussions about step asides and those kinds of fights. So we’ll have to see.
“But that looks very unlikely now because obviously of the Dillian Whyte situation, which AJ is pleased about because he didn’t really want to have those conversations unless I presented them to him.
“So if that’s not the case, he moves forward with what he wants, which is the Oleksandr Usyk rematch.”
Meanwhile, Usyk’s manager Sergey Lapin believes his client will beat Joshua again, claiming the Ukrainian is ‘constantly improving and getting better every training day’.
He said: “I have known Alexander for more than 20 years. I have been there and seen all of his successes in boxing.
“One thing that sets him apart is he processes information and adapts to the fighter in front of him very, very quickly.
“It sometimes seems to me that he is from another planet – he is that good.
“Despite the fact that he has a huge amount of experience and fights behind him, he is constantly improving and getting better every training day.
“I have seen and know what Usyk is really capable of, and the version of Usyk in the fight with Anthony Joshua was 60-70 percent of his potential.
“So yes, Usyk can really be better.”