The fight had initially been discussed for November but, with negotiations over the venue dragging on, it now looks set for December.
Staging an open-air stadium fight in the UK at that time carries immense risk.
While Wembley offers unmatched prestige, exposing tens of thousands of fans and a massive international broadcast operation to potentially freezing temperatures, wind and rain was deemed unacceptable.
Moving the event indoors to an arena like London’s O2 would eliminate weather risks, but at the cost of sacrificing tens of thousands of ticket sales.
The Principality Stadium’s retractable roof allows organisers to capture the immense scale, atmosphere and gate revenue of a stadium show while offering full protection from the elements.
The venue’s official seated capacity is just under 74,000, but boxing configurations allow for even larger crowds.
Joshua has already proven he can sell out the venue, having defended his WBA and IBF titles there against Carlos Takam in front of nearly 80,000 fans in 2017 before adding the WBO belt against Joseph Parker five months later.