Wilder will be making the seventh defence of his WBC heavyweight crown in New York on March 3 when he takes on Luis Ortiz.
Joshua, meanwhile, has a jam-packed schedule in 2018 as he seeks to unify the heavyweight division.
A clash with New Zealander Joseph Parker will be his first test on March 31.
Joshua has so far avoided attempts to fight across the Atlantic and Wilder has called out the Brit many times, urging him not to duck the challenge.
And Wilder has now upped the ante, suggesting Joshua would be a “fake” if he didn’t fight in the States.
“He may have his country behind him and that’s it,” Wilder told ESPN.
“Does he want to be remembered as a country-wide champion? Because he’s not worldwide [champion].
“Over here in America they don’t even know his name. They just know him as a big guy from England. That’s fact.
“I need him and he needs me at the end of the day, unless he doesn’t want to unify.
“Unless he wants to stay over his side of the pond and let people gravitate to him and be a fake sign of what he [says he] is.
“But he will never be a global icon. You will never be a world-wide figure without me. All roads lead to Deontay Wilder.”