Tyson once offered a Central Park zookeeper $10,000 (£7,191) to let him into the gorilla enclosure and fight a 300lb gorilla for bullying other animals.
Browsing: Iron Mike
Holyfield, who turns 59 next month, had stepped in as a late replacement for Oscar De La Hoya, 48, who pulled out of facing Belfort, 44, with coronavirus.
The 53-year-old is rumoured to be gearing up for a sensational return to boxing, 15 years after he hung up his gloves.
Tyson, 53, has recently been training with MMA coach Rafael Cordeiro, and is reportedly set for a stunning comeback in order to raise money for charity.