Tony Bellew will challenge Ukraine's Oleksandr Usyk for the undisputed world cruiserweight title at Manchester Arena on November 10.
Former WBC cruiserweight champion Bellew is stepping back down a division after his two heavyweight victories over David Haye.
And he accepts he will start as underdog against the 2012 Olympic gold medallist who has taken the professional ranks by storm.
Bellew told Sky Sports: 'I'm going into this fight with absolutely nothing to lose because the whole world thinks I'm going to get smashed.
'There is no greater test than Oleksandr Usyk, one of the most feared men in boxing.
'I have everything to gain. On November 10, I'm going to do something that no-one has ever done before - I'm going to knock out an undisputed cruiserweight champion of the world.'
Usyk won the WBO title in his 10th fight before adding the WBC with victory over Mairis Briedis in the World Boxing Super Series semi-final.
He added the IBF and WBA crowns by beating Murat Gassiev in the final.
Usyk said: 'I've been preparing for this fight for a long time and I'm delighted that we've got the venue and the date finalised. I cannot wait to fight in the UK.'