Anthony Joshua believes a fight against Deontay Wilder is "95 per cent" likely to happen this year.
Wilder made a $50million offer to Joshua last month to agree a bout that would crown an undisputed world heavyweight champion, and negotiations have taken place since.
"The fight is going to happen. Ninety-five percent this year," Joshua told Sky Sports.
"I'm really, really, really interested.
"You can't talk about finances anymore because I'm well aware there is financial gain in this fight. So, let's put that aside and look at the devil in the detail.
"You can't just offer me a buy-out clause. I'm not here to sell my belts, let you take control of the event - that's not what I'm about."
Joshua unified the IBF, WBA and WBO belts against Joseph Parker in March at Cardiff's Principality Stadium, a third fight in 11 months that sold nearly 250,000 tickets combined.
WBC champion Wilder, unbeaten in 40 fights, most recently stopped Luis Ortiz and has staged three title defences in New York City.
"Let's build this fight to its true potential," Joshua said. "I want the fight in the UK and they want it in America.
"We've got a long time to finalise it, because it will [potentially happen at the end of the year]. We're working tirelessly on it.
"I'm really interested in that fight."
Joshua was ringside to see Tony Bellew stop David Haye in the fifth round of their rematch at London's O2 on Saturday.