Evander Holyfield, former world heavyweight boxing champion, says Anthony Joshua and Deontay Wilder stand to make as much as $250m if they face each other.
But for that to happen, Joshua will have to beat Joseph Parker in a heavyweight unification bout on March 31 at the Principality Stadium, Cardiff.
Holyfield said if Joshua overcomes Parker, the mega bout against Wilder must take place as soon as possible.
The boxing legend said the British boxer should fight the American while the money is there.
“I don’t know if Joshua is going to beat Parker,” Holyfield told BBC Sport.
“All three of them have got the mindset and all three [Joshua, Wilder and Parker] are youngish too.
“If Joshua wins [against Parker], I think he and Wilder can both make about $250million so why not make the money while the money’s there?
“In being a great fighter you make money because you have proven to the people you are the best out there.”
Wilder, the World Boxing Council heavyweight champion, and Joshua have been involved in a war of words but are yet to agree on a date for the unification fight.
Joshua is the current holder of the WBA and IBA titles.