Lennox Lewis knows a thing or two about fighting under the bright lights, besting Evander Holyfield to become the undisputed heavyweight champion of the world and knocking out Mike Tyson to defend his title in what was, at that time, the highest-grossing bout in pay-per-view history.

You'll have to excuse him, then, if he's getting a little impatient for an Anthony Joshua vs. Deontay Wilder fight.

Delayed until at least April 2019 after three months of public negotiations and disputes, the highly anticipated heavyweight unification bout will have to wait until after a September bout between Joshua (21-0) and Alexander Povetkin (34-1) is expected to take place. And the 52-year-old Lewis, who facilitated his fair share of big-name battles during his own days in the ring, took to Twitter on Thursday to join the boxing world's collective sigh.

"When I was champ, I wanted to face the best to show the world who's best. Period," Lewis said. "I've heard them both speak on it, but I've also seen that AJ (Joshua) has changed his tune ... If both sides wanted this fight, it would be happening. End of story."

Lennox acknowledged promoter Eddie Hearn's claim that Wilder can still agree to the historic unification showdown for a 2019 date in England. But he suggested "we need action, not talk" from both sides of the proposed fight, which, as CBS Sports' Brian Campbell noted, "would be the biggest fight the sport could make and the most anticipated the division has seen in over 15 years."