Britain's Derek Chisora will fight unbeaten Ukrainian Oleksandr Usyk in a heavyweight bout on 23 May at the O2 in London.
The fight had been expected to take place in March but was put back after Usyk suffered an injury in training.
Chisora, 36, has not fought since a fourth-round stoppage victory over compatriot David Price in October.
Usyk, 33, is a former undisputed cruiserweight champion who stepped up to heavyweight last year.
He comfortably won his heavyweight debut in October by stopping Chazz Witherspoon in the seventh round, extending his career record to 17 wins and no defeats.
It was Usyk's first fight since he defended all four world cruiserweight titles against Britain's Tony Bellew in November 2018.
Chisora has a record of 32 wins and nine defeats in 41 professional bouts.
BBC Sport boxing reporter Luke Reddy
This fight has hardcore boxing fans excited.
Let's not forget Usyk is mandatory challenger to Anthony Joshua for the WBO world title. Joshua is of course first taking care of his IBF mandatory in Kubrat Pulev on 20 June.
But were Usyk to win, there will be a momentum behind him to get his tilt at Joshua very, very soon. The fact this is in Britain and will gain big exposure will only boost his case if he wins well.
If Chisora were to win and keep the good form he has found late in his career going then maybe Joshua - his friend of old from Finchley ABC - could even come into sight for him.
There's also an intriguing clash of styles given Chisora's hustle, bustle and brawling ways will meet the slick, graceful movement of Usyk.
All credit to Usyk for risking his mandatory position in a fight against such a tough man. He could have sat and waited for Joshua. He must feel he can wow us at heavyweight, just like he did at cruiser.