Heavyweights Anthony Joshua and Deontay Wilder are in talks to fight on the same card in Saudi Arabia on 23 December.
Wilder's team are "hopeful" a deal can be finalised as organisers aim to fill a gap on the card.
Tyson Fury v Oleksandr Usyk was set to headline, but Fury's difficult encounter with Francis Ngannou last month derailed those plans.
Organisers are very confident a deal is close with Joshua and Wilder.
Queensberry promoter Frank Warren said this week that 23 December would be a "historic" night for boxing.
Turki Alalshikh, of Saudi Arabia's General Entertainment Authority, is leading discussions with Joshua and Wilder alongside Queensberry Promotions.
Briton Joshua, 34, is promoted by Matchroom Boxing and Eddie Hearn, while American Wilder has spent most of his career with Premier Boxing Champions and adviser Al Haymon, as well as being managed by Shelly Finkel.
Hopes are high that a deal will be done for Joshua and Wilder to fight separate opponents and could be announced shortly as 23 December is only six weeks away.
The deal could pave the way for Joshua and Wilder to fight each other in 2024, although the possibility of Joshua-Wilder appearing on the same card as Usyk-Fury is unlikely.
WBC champion Fury and IBF, WBO and WBA belt holder Usyk are expected to fight in a long-awaited undisputed heavyweight bout by February in Saudi Arabia.
Earlier this year Joshua and 38-year-old Wilder were in talks with Saudi Arabia-based Skills Challenge about fighting before discussions collapsed. Alalshikh's outfit has now emerged as the power broker for boxing in the country.
Joshua and Wilder are former world champions but are on the comeback trail since losing their world titles to Usyk and Fury respectively.
Fury, 35, is unbeaten in 35 fights, while former undisputed cruiserweight champion Usyk is undefeated in 21 bouts.