Fury completed a stunning seven-round demolition of knockout specialist Deontay Wilder in Las Vegas last month to collect the WBC title, while countryman Joshua holds the other three major heavyweight belts after avenging his defeat to Andy Ruiz with a comprehensive points win last December.
Usyk, who is like Fury undefeated and has a London 2012 gold medal in common with Joshua, cleaned out the cruiserweight division and has similar designs having stepped up to take on boxing's big men.