The Bellator London bill featuring NI pair James Gallagher and Leah McCourt on 16 May has been postponed because of the ongoing Covid-19 pandemic.
Gallagher was scheduled to face England's Cal Ellenor in the headline bout at the SSE Arena in Wembley.
McCourt, who was set to take on New Zealander Janay Harding, said she is "gutted" at the postponement.
The event was also set to feature the mixed martial arts debut of former England rugby star James Haskell.
- Gallagher needs only 35 second to beat Salazar
- Gallagher bout with Ellenor rescheduled for London
- McCourt lands unanimous decision win over Ruis
This will be the third time a fight between James Gallagher and Ellenor has been postponed.
The pair were originally due to face each other at Bellator Dublin in September 2019, but because of complications surrounding Ellenor's pre-fight medicals, the Sunderland fighter was unable to compete.
'The Strabanimal' went on to submit late replacement Roman Salazar in just 35 seconds.
Both fighters were due to meet in a rescheduled bout in February of this year at the 3Arena in Dublin, but Gallagher was forced to withdraw with a back injury.
"I'm absolutely heartbroken that the show is cancelled, but I must continue," said Gallagher.
"I'll never stop - the work will continue and I'll be ready for when they need me."
McCourt replaced the 23-year-old as the headline fight and went on to secure a unanimous decision victory over Judith Ruis.
McCourt was hoping to build on that momentum when she faced Janay Harding and said on social media that the "heartache and disappointment is a feeling I am all too familiar with. Not surprised but not any less gutted."
The Saintfield woman added that she thought it was the correct decision as the "safety of fighters and amazing staff must be priority".
Bellator announced it was also forced to postpone their May 242 and 243 shows in California as "the health and safety of our athletes, fans, partners and staff remains our top priority".
The organisation added that it "will continue to monitor the situation closely and fully intendeds to reschedule the events as soon as possible".