David Haye will confirm his expected return to boxing at a press conference on Thursday.
On Tuesday the British heavyweight called the media for an announcement on Thursday, where he is expected to make official his return to the ring at the end of June or beginning of July.
Haye's opponent for that return fight is not yet known, although names including WBA contender Alexander Povetkin and British prospect Tyson Fury have been mentioned.
In a statement his promotions company, Hayemaker, insisted that Haye had been against a return in recent months, but added: "That is soon to change, however.
"Heavyweights be warned, 'The Hayemaker' is back."
Haye, 32, has persistently stated that he would only return for a fight with one of the two Klitschko fighters but, with Wladimir unwilling to offer a rematch and Vitali proving elusive, he will have to earn another title shot by beating other prospective contenders.
At the weekend Haye's trainer, Adam Booth, had acknowledged that the Brit was closing in on a return to action, having been out of the ring since beating Dereck Chisora in a controversial fight at Upton Park last July.
"David is definitely doing some serious thinking," Booth said. "He will make a decision very soon - in the next ten days or so."