The winner of the WBA-IBF world heavyweight clash between Anthony Joshua and Wladimir Klitschko may not be allowed to hold both titles for long.
Both world governing bodies are ordering the winner of the April 29 Wembley showdown to fight different opponents, which may result in either Joshua or Klitschko losing one of the belts.
Germany-based promoters Kalle and Nisse Sauerland have confirmed via Twitter that their Bulgarian fighter Kubrat Pulev must face the winner of Joshua-Klitschko.
According to the Sauerlands, Pulev (24-1, 13 KOs), who is the IBF's highest-ranking boxer below champion Joshua, must face the winner with no interim fights, as he is the mandatory challenger.
CONFIRMED: winner of #JoshuaKlitschko must face IBF Mandatory challenger Kubrat Pulev in the next fight (no fights in between permitted)👌💥👍— Kalle+NisseSauerland (@SauerlandBros) December 22, 2016
Their announcement comes a few days after the WBA claimed that the winner of Joshua-Klitschko must next fight unbeaten Cuban Luis Ortiz, who is signed to Joshua's British promoter, Eddie Hearn.
It is a complicated situation that Briton Joshua (17-0, 17 KOs) or Ukrainian Klitschko (64-4, 53 KOs) may find impossible to resolve and remain in possession of both world-title belts.
Should Joshua and Klitschko decide on a rematch, it would complicate matters further.
Joshua, 27, will make a third defence of his IBF belt, against Klitschko, 41, after winning the title last April.
The WBA "super" title, the WBA's most prestigious belt, will also be on the line after Briton Tyson Fury relinquished it earlier this year when he withdrew from a rematch with Klitschko.
Fury's surprise points win over Klitschko 13 months ago ended the Ukrainian's nine-and-a-half-year reign as world champion and earned him the IBF, WBA and WBO belts.
Fury was stripped of the IBF belt when he announced he would face Klitschko in a rematch.
The winner of Joshua-Klitschko could face the same fate after their clash at Wembley, which has sold 50,000 tickets and could be watched by a record crowd of 90,000.
Pulev, 35, has registered four wins since being knocked out by Klitschko in the fifth round of an IBF title fight in November 2014. He won a split decision over Briton Dereck Chisora for the European crown last May.
Ortiz (27-0, 23 KOs), 37, has previously held the WBA interim title and would be an easy fight for Hearn to make.
"Hopefully I defeat Klitschko, and then I can fight Ortiz," said Joshua.
"I will be watching him for sure, because he is a competitor in the division that I could face sooner or later, so I have to put him as a priority.
"If we fight Ortiz, it would be a good scrap, because I like fighting southpaws."