In March, Bellew recorded an 11th-round stoppage win over Haye, who sustained a torn Achilles midway through the bout, but the pair have come to an agreement over a second clash at the end of the year.
Haye is desperate for revenge against his rival, but the two-weight world champion has suggested a lack of understanding for Bellew's reasoning for a rematch.
The 36-year-old told Sky Sports News: "We are tough guys and we are willing to put it on the line again and he's doing it again yet he is a multi-millionaire now after the first fight, so is he going to have the same desire going into this rematch than he had for the first one?
"The first time around he said it to anyone that would listen, that his motivation was about securing the future of his family - like I did a few years ago.
"He has finally done that now, so he is going back into the ring, but what is his motivation? Well, he says he's got a screw loose, well anybody who has a screw loose doesn't know he's got a screw loose." I don't know what his desire is. He says he doesn't like boxing, he doesn't like training, but I do, I love it."