Los Angeles - Deontay Wilder told Anthony Joshua "the money's in the bag" as prospects rose on Wednesday of a blockbuster world title unification bout between the unbeaten heavyweights.
In a Twitter video posted Wednesday, America's World Boxing Council world champion Wilder backed up reports that his camp had emailed Britain's Joshua and his promoter Eddie Hearn an offer of a minimum of $50 million.
"I've got something special for you," Wilder tells Joshua in the video. "By the way, all the money is in the bag. I expect you'll be a man of your word."
Joshua, who unified the World Boxing Association, International Boxing Federation and World Boxing Organization heavyweight titles by out-pointing New Zealand's Joseph Parker on March 31, had already been recorded saying he'd "take $50 million up front" to fight Wilder.
The Los Angeles Times reported that Wilder promoter Lou DiBella had confirmed the offer for a fight in the United States sometime between September and December.
"We'll see how badly he wants the fight," DiBella told the newspaper. "Anthony Joshua has said he'd accept this offer. If Eddie Hearn is not looking to stop it from happening, they now have an extraordinary offer to consider."
ESPN reported that both camps had confirmed the offer, adding that it was for one fight, with no rematch clause, and would have to be the next bout for each fighter.
The winner of a Joshua-Wilder bout would be the first man to hold all four major heavyweight titles simultaneously, and Joshua told the BBC this month that he'd rather face Wilder than Russian Alexander Povetkin, the WBA mandatory challenger.
Joshua, 28, won his first world title in 2016 and has made five defences, taking his record to 21-0 with 20 knockouts.
Wilder, 32, improved to 40-0 with 39 knockouts when he knocked out previously unbeaten Cuban Luis Ortiz in the 10th round in Brooklyn, New York, on March 3.