Kubrat Pulev has had to withdraw from an upcoming bout against Anthony Joshua due to injury.
Joshua, 28, will now defend his IBF and WBA heavyweight world titles against Carlos Takam on 28 October at Cardiff's Principality Stadium.
The Cameroonian-French Takam, 34, has been on standby for the fight and now has the opportunity to fight for belts after Bulgarian Pulev suffered a shoulder injury in sparring.
It will be Joshua's first fight since stopping Wladimir Klitschko at Wembley Stadium in April, adding the WBA title to the IBF belt he claimed in 2016.