Anthony Joshua could face IBF world champion Charles Martin on April 9, according to his promoter Eddie Hearn. The unbeaten Brit has been holding talks with a number of parties for his next fight and Hearn has revealed negotiations with Martin are currently ongoing.

Martin, 29, won the vacant belt in January, when his opponent Vyacheslav Glazkov suffered a knee injury early in the fight. For Joshua – whose last opponent was long-time rival Dillian Whyte – a fight against Martin would represent a significant step up in quality.

"We were due to announce his opponent [yesterday]. There have been a lot of people calling Anthony Joshua out, claiming they want to fight him and we need to find out which of those are real," Hearn told Sky Sports.

"There have been some big opportunities that have been bandied around, some of which I think people felt we wouldn't be willing to take but after speaking to Anthony and his trainer, he's more than willing to take."

Hearn suggested Joshua could face Martin (23-0-1) at London's O2 Arena in April. "He's IBF world champion and he's been calling Anthony Joshua out. It shows the size of Anthony Joshua, you've got a world champion there calling Anthony Joshua out," Hearn said.

"He's made some noise saying: 'We've offered Anthony Joshua the fight.' It doesn't really work like that. You phoned us up and told us you want an extortionate amount of money and then you'll fight him so we're working the numbers on that fight."

Hearn admitted the fight against Martin would represent a "huge gamble" for the gold medal-winning star. "It's the 16th fight of Anthony Joshua's career. Is it too early? It's a huge gamble. Two relatively inexperienced guys. I think Charles Martin is 6ft 5in and Anthony's 6ft 6in. They both punch with immense power. It's one of those you might have to watch through your fingers," he said.

"Anthony Joshua wants the challenges. Sometimes it's difficult to win a world heavyweight title. Now you have a guy who appears to be prepared to come to London on 9 April so we have to take it seriously."

Hearn insisted, though, that there are other fights in the offing. "He's not our only option. We've got three or four others that we're looking at but over the next 48 hours, we'll find out exactly where we're at. Could it be a shot at the world heavyweight title? Just maybe," he said.