Anthony Joshua has been warned that Oleksandr Usyk has asked his amateur mentor Anatoly Lomachenko to mastermind a stunning world title triumph.
Joshua is set to defend his WBA, IBF and WBO heavyweight titles against Usyk, with Tottenham Hotspur Stadium in London expected to stage the fight on September 25.
Usyk had been prepared by Yuri Tkachenko for his last points victory over Derek Chisora in October, but has now returned to Anatoly, the revered trainer and father of his close friend, pound-for-pound star Vasiliy Lomachenko.
Lomachenko's promoter Bob Arum revealed the change in Usyk's team, telling Sky Sports: "Let me caution you something, because even though I don't promote him, I consider him a really good friend and that's Oleksandr Usyk, who the reason I know him so well is he is the best friend of Vasiliy Lomachenko.
"Egis Klimas, who is the manager of both, I talk with him and he has talked with the father of Lomachenko, who he calls 'Papa Lomachenko' who was the trainer of all these Ukrainian Olympians and he's agreed to properly train Usyk for this fight.
"I'm telling you, 'Don't think that Joshua is in a cake walk. He has a really tough fight with Usyk, who is a terrific boxer.'
"His father wouldn't train anyone else, but he will train Usyk, because Usyk is like family."
Lomachenko, who knocked out Masayoshi Nakatani last weekend, has suggested that Joshua's size advantage could work against him if he can't pin down Usyk.
"Of course I believe he can win," Lomachenko told Sky Sports.
"He has a very big chance but it won't be easy because Joshua also knows what he must do in the ring.
"Joshua also knows boxing, he has also had amateur experience.
"It will be an interesting fight, very interesting."
Asked about Joshua's considerably bigger and heavier frame, Lomachenko replied: "But Oleksandr is much faster.
"It will be a fight between styles."
Joshua exclusively told Sky Sports when asked about what dangers Usyk will bring: "None. I fear none of them.
"He doesn't bring anything that I haven't seen before.
"Two arms, two legs, a brain and a bit of heart. That's it, so let's get it on.
"He's a good fighter. I'm challenging myself in training - it's not so much his challenge.
"I will go in there not thinking about the task ahead. That's something I can't do. I don't want to overcomplicate this task.
"I will believe in myself, go in there and do what I know I can do.
"People don't know what I can do until they are in the ring with me.
"I'll show what I'm about. I will tick another box when the final bell goes - if it does go!"