0221 GMT June 23, 2018
Three of the four world heavyweight belts will be on the line when IBF and WBA 'Super' holder Joshua takes on WBO champion Joseph Parker at the Principality Stadium, on March 31, Sky Sports reported.
Wilder will be ringside in Cardiff as part of the punditry team if he beats Luis Ortiz on March 3 and has been keen on fighting Joshua for years.
"The big fight is me and Joshua, of course, and that's who I want," said Wilder. "I've been calling him out for almost two years now. A lot of people think this just started, but it didn't, it started years ago.
"I told people to do their research and their history, then they'll come up with the facts instead of the fiction. But, I want to unify by all means necessary, whether [Joseph] Parker has it or Anthony [Joshua] has it.
"It doesn't matter who has it, I want to unify and I can't be clearer than that."
Wilder will defend his WBC world heavyweight title belt for a seventh time against Ortiz at the Barclays Centre, New York, and he has issued a warning to the Cuban ahead of their bout.
"Luis Ortiz you about to go down," he added. "I'm going to use you as an example for the rest of them.”