Dereck Chisora will face David Price on 26 October in a British heavyweight bout where both men will risk their careers, says promoter Eddie Hearn.
Chisora, 35, was set to face Joseph Parker until the former world champion withdrew following an illness he believes stemmed from a spider bite.
Price, 36, has stepped in and enters the bout off a run of three victories.
The bout, at London’s O2 Arena, will form part of the undercard to the world title fight between super-lightweights Josh Taylor and Regis Prograis, which is the final of the World Boxing Super Series.
Chisora has previously expressed his displeasure at not being the night’s main event and threatened to walk away from competing if he was not paid more.
Price – who has 25 wins from 31 outings – and Chisora – with 31 wins from 40 contests – have both built momentum in recent fights with strong displays.