The 35-year-old had returned to his home nation to help defend against the Russian invasion, but revealed last week that he intended to press ahead with the planned Joshua rematch.
“That’s how I will help my country more and it’s better than being in territorial defence and running around Kyiv with a machine gun,” said Usyk in a message on social media.
“Dear friends, many of my friends and close ones called me and supported me in this. Haters, I wish you well and wish you happiness, joy and peace.
“Everything will be with God’s blessing. Everything will be Ukraine. Wishing everyone well.”
“Many things will depend on how fast we manage to ink the papers.metasports
“The good thing is that Usyk is already in Europe to start his preparation.”
“This location is under discussion at the moment,” Krassyuk told Sky Sports.
“Late June is also the timing we are considering now.
Joshua could now be heading back to Saudi Arabia after regaining his WBA, IBF and WBO heavyweight belts in a rematch with Andy Ruiz Jr in Diriyah in December 2019.