Eddie Hearn expects Anthony Joshua's proposed fight against Alexander Povetkin to be "finalised in the next 72 hours", but has warned that an agreement for the superfight with Deontay Wilder could still be a month away.

Russia's Povetkin, the mandatory challenger to the Watford star's WBA heavyweight title, is preparing for a fight in the UK in September.

Should a date be secured it will come with an agreement for WBC champion Wilder to then come to Cardiff's Millennium Stadium in February to fight for all four heavyweight titles in what would prove the most significant match-up in the world.

Hearn remains in discussions with both camps in an unusual attempt to agree both fights, and there remains the possibility of Wilder being the first of the two opponents.

But it is increasingly likely that Povetkin will come first and that Joshua will begin his training camp before their fight is officially announced, so that both can be confirmed at the same time.

"The Povetkin deal will be finalised in the next 72 hours," Hearn said. "The Povetkin deal is virtually done. The Wilder one is not, but we're talking every day.

"Joshua would like to fight in September. The Wilder fight doesn't really work in September, mainly because of the Canelo (Saul Alvarez) fight. The pay-per-view doesn't really work out.

"If he fights Wilder (first) it'll be October, November in the UK, and if he fights Povetkin it'll be in September. If it's Povetkin next, the Wilder fight will definitely be signed before we go into that fight.

"Wilder understands he has to go where Joshua tells him to and at the moment Joshua's telling him, 'You have to come to the UK'. He knows, he's up for that, but there's a lot of things that have to be worked out.

"A deal will be done with Wilder in the next month, but we will probably move on a Povetkin fight before that. Wilder would be December at the earliest, probably February."