The unbeaten Brit heads into the April 29 showdown at Wembley Stadium looking to defend a perfect record, which stands at 18 professional fights and 18 victories via knockout.
Joshua has vowed to "step up" in the biggest bout of his career to date, and Hearn is already eyeing up future opponents for the IBF world heavyweight champion, who intends to stick around for the next decade.
"Everything is just on the line on April 29," he told Sky Sports News. "AJ talks about having 10 years left in boxing, so part of me doesn't want to rush, but we're rushing into the Klitschko fight. Why not keep going?
"Deontay Wilder will be ringside - that's a natural fight. Joseph Parker is another fight as well. It's all about winning, but he certainly wants to be in the biggest fights possible over the next 10 years."
Hearn was quiet when asked if a rematch clause was included in the fight contract for Joshua and Klitschko, which will be watched by British boxing's biggest post-war crowd.