Oleksandr Usyk announced via Instagram on Tuesday that he is vacating the IBF heavyweight title, which now will be on the line when Anthony Joshua fights Daniel Dubois on Sept. 21 at London's Wembley Stadium.
IBF president Daryl Peoples confirmed to ESPN that the heavyweight title was vacant, but refuted reports that Dubois had been elevated to champion, saying no ruling has been made.
The Joshua-Dubois bout will be formally announced at a news conference Wednesday and will be the first Riyadh Season event in the U.K. The first such event outside the kingdom is the Aug. 3 Terence Crawford-Israil Madrimov bout in Los Angeles.
Ukraine's Usyk ascended to the top spot in ESPN's pound-for-pound rankings when he defeated Tyson Fury via split decision last month in Riyadh, Saudi Arabia, for the undisputed heavyweight championship.
Now, all four belts won't be on the line when Usyk meets Fury in the Dec. 21 rematch in Riyadh. The WBC, WBA and WBO titles will be up for grabs, but the IBF title will be contested between Joshua and Dubois.
Usyk's mandatory IBF title defense was overdue, and it was ruled going into his fight with Fury that the winner must face the mandatory challenger next or be stripped. With a two-fight deal in place, Usyk's move Tuesday was expected.
Dubois scored an eighth-round TKO victory over Filip Hrgovic, then the No. 1 contender, earlier this month in Riyadh to win the IBF interim title.
"Anthony and Daniel, listen: I know, IBF title important to you," Usyk said in his video Tuesday, calling his decision to vacate the belt "my present to you on Sept. 21."
Usyk (22-0, 14 KOs) already owns wins over Joshua and Dubois. He scored consecutive decision victories over Joshua in 2021 and '22 before he knocked Dubois out in Round 9 of their August meeting.
Joshua (28-3, 25 KOs) and Dubois both hail from England. Joshua's past two fights took place in Riyadh, and now he'll return to the 90,000-plus-capacity Wembley Stadium, where he has headlined twice. Joshua, 34, is a former two-time heavyweight champion and ranked No. 3 in the division by ESPN. He's coming off a spectacular second-round knockout of former UFC champion Francis Ngannou in March.
Dubois is ESPN's No. 6 heavyweight. His other career defeat came against Joe Joyce, a 10th-round knockout in 2020.