Daniel Dubois and Oleksandr Usyk are in talks to fight at Wembley Stadium on 12 July.
The rival heavyweight champions hold all four major world titles between them, with Dubois the IBF champion and Usyk the WBA (Super), WBO and WBC belt holder.
Usyk, 38, is undefeated in 23 fights and has a win over Dubois, stopping him in August 2023.
Their rematch would be for the undisputed heavyweight title as well as offer 27-year-old Dubois the chance of revenge.
While talks are ongoing between both camps, no contracts have been signed.
Dubois has won three fights since his defeat by Usyk, securing a knockout in each of them.
If the Londoner cannot reach terms with Usyk, he will be ordered by the IBF to face 49-fight veteran Derek Chisora who the IBF has as its number one contender.
The projected date in July comes in the middle of a busy period in sport with Katie Taylor’s trilogy fight against Amanda Serrano on 11 July in New York, the final weekend of Wimbledon on 12 and 13 July and the Women’s Euro 2025 also under way.
Usyk is keen to fight for the undisputed title once more before he retires after he was forced to vacate the IBF belt before his rematch with Tyson Fury last December.
The Ukrainian, who was also undisputed champion at cruiserweight, has suggested he will retire after two more fights.
Dubois was due to defend his IBF belt against Joseph Parker in February, before illness caused him to withdraw from the contest in fight week.
Usyk’s most recent fight was his second win over Fury, when he confirmed himself as the number one heavyweight in the world.
No British fighter has held the undisputed heavyweight title in the four-belt era and the last Briton to be undisputed heavyweight champion was Lennox Lewis in 1999.
