Oleksandr Usyk has been ordered by the WBO to defend his undisputed heavyweight crown against Joseph Parker.
The WBO sent out a letter to both camps on Tuesday to confirm the mandatory title defence, which was subsequently released to the public on Thursday.
A statement from WBO president Gustavo Olivieri reads: “The championship committee has ruled that Usyk must fulfil his mandatory against interim champion Joseph Parker.
“Therefore, a formal negotiation order is forthcoming. The interim status will be terminated upon the completion of the mandatory bout.
“By virtue of his ruling, the WBO enforces expeditiously the one world champion per weight class policy.”
Both parties now have 30 days to agree on terms.
Failure to do so will result in the committee ordering a purse bid, with a minimum offer of $1million.
Usyk unified the WBC, WBA, IBF and WBO belts last weekend by dispatching Daniel Dubois in front of 90,000 fans at Wembley Stadium.
He can opt to reject the WBO’s order and fight somebody else.
However, he will be forced to vacate his red and gold strap if he chooses to do so.
The WBO is next up in the sanctioning body rotation system, while Parker is the WBO interim champion.
The Kiwi picked up the belt by outpointing Zhilei Zhang last March.
Parker also previously reigned as the full WBO champion between 2016 and 2018 before being dethroned by Anthony Joshua in Cardiff.
He was written off by several members of the boxing fraternity after suffering a devastating stoppage loss to Joe Joyce in 2022.
However, he has re-established himself as a top-rated heavyweight over the last three years.
Victories over Deontay Wilder, Zhang and Martin Bakole in his last three outings have seen him soar up the Ring Magazine heavyweight rankings to No.3.
He will now have to wait and see whether Usyk intends to accept the call to fight him in what is expected to be the Ukrainian’s final bow as a professional.
“Nothing is next,” Usyk said after his win over Dubois. “It’s enough, next, I don’t know. I want to rest.
“My family, my wife, my children, I want to rest now. Two or three months, I want to just rest.
“[Then] maybe it’s Tyson Fury. Maybe we have three choices: Derek Chisora and Anthony Joshua. Maybe Joseph Parker.
“Listen, I cannot now say because I want to go back home.”