Oleksandr Usyk announced on Instagram that he has vacated his IBF heavyweight title, a belt that will now be contested when Anthony Joshua and Daniel Dubois face off on Aug. 21 in London.

Usyk successfully defended his IBF, WBA and WBO belts in a split decision victory over Tyson Fury last May and won the WBC belt off the ex-champ as well. He has a two-fight deal with Fury, and that next bout will go down on Dec. 21 in Riyadh, Saudi Arabiia.

However, as ESPN's Mike Coppinger explained, the IBF had to strip Usyk of the belt if he did not face its mandatory challenger (Dubois) next. Since Usyk is already set for a Fury bout, the drop here was inevitable.

Usyk had a little fun with the announcement.

"Anthony and Daniel, listen: I know, IBF title important to you," Usyk said, adding that this was "my present to you on Sept. 21."

The 21-2 Dubois, 26, is the interim IBF heavyweight champion after beating Filip Hrgović via eighth-round TKO on June 1. All but one of his victories have come via knockout. He previously fought Usyk for the WBA, WBO and IBF belts last August but lost via ninth-round knockout.

The 28-3 Joshua has held the WBA, IBF and WBO titles on two different occasions. He successfully defended all three together three times before dropping the belts in a stunning seventh-round TKO to Andy Ruiz Jr. in June 2019.

Joshua won them back via unanimous decision six months later, but he lost them again to Usyk in Sept. 2021 and then fell when the two squared up again in Aug. 2022. The first loss was via unanimous decision, and the second was by split decision.