Anthony Joshua's bout against Kubrat Pulev on June 20 in London has been postponed because of the coronavirus pandemic.
Joshua was due to take on the Bulgarian for the WBA, WBO, IBF and IBO world heavyweight titles at the Tottenham Hotspur Stadium.
However, promoter Matchroom has announced that the fight will be rescheduled for a later date which has yet to be confirmed.
This is the second time Pulev has missed out on the opportunity to take on the Briton after a shoulder injury forced him out of a world title bout in October 2017.
A statement from Matchroom read: "Anthony Joshua's defence of his IBF, WBA, WBO and IBO heavyweight world titles against mandatory challenge Kubrat Pulev secheduled to take place at the Tottenham Hotspur Stadium on Saturday June 20 has been postponed.
"A new date for the event is currently being worked on.
"We will announce any updates in due course and continue to explore the possibility of hosting this fight at the Tottenham Hotspur Stadium."
The 30-year-old fell to a shock seven-round defeat at the hands of Andy Ruiz Jr at Madison Square Garden in June last year to relinquish his WBA, WBO and IBF world titles.
However, he reclaimed the belts with an accomplished performance in Saudi Arabia as he defeated the Mexican by points to set up a potential clash with Tyson Fury, the holder of the WBC World title.
The clamour for an all-British world title fight was ramped up even further when Fury claimed the WBC crown from Deontay Wilder in February but Joshua was ordered to take on mandatory challenger Pulev.