David Haye and Dereck Chisora are set to meet in a heavyweight boxing clash at West Ham's Upton Park on Saturday, 14 July.
The British heavyweights were involved in a brawl
Chisora's defeat by Vitali Klitschko in Munich in February.
The pair do not have licences to fight in Britain but the bout has been authorised by the Luxembourg Boxing Federation.
BBC Sport looks at how and why the fight has been allowed to happen.
Why do the fighters not have licences to fight in Britain?
Chisora had his licence withdrawn by the British Boxing Board of Control
because of a number of controversial incidents before and after he lost his fight to Vitali Klitschko in Munich in February.
The scuffle with Haye was the third controversial incident involving Chisora to occur in two days in Munich.
The first was when he slapped Klitschko at the weigh-in, and then, moments before the fight, he spat water in the face of his opponent's brother Wladimir inside the ring.
He has appealed against the decision to withdraw his licence, although that hearing has been put back to July.
Haye relinquished his licence when he retired in October 2011,
three months after
losing his WBA title to Wladimir Klitschko in Hamburg.
Why are they allowed to fight if they do not have licences?
"Dereck Chisora's appeal against the removal of his licence has been delayed and Frank Warren is furious at how the British Boxing Board of Control have dealt with the whole matter.
"That Chisora and David Haye should ultimately benefit from the shame in Munich is difficult to stomach for many but it's the nature of boxing that such controversy will build the fight into the biggest of the year in this country."
Because European Union freedom of trade laws permit the fight to be held in the United Kingdom and they have been given licences by the Luxembourg Boxing Federation.
"It is a way of dancing around the regulations," said BBC boxing commentator Mike Costello.
Chisora's manager Frank Warren said: "I have legal obligations to Chisora and I won't have these compromised by the British Boxing Board of Control. They said he was able to apply for a licence in another jurisdiction at the hearing and that is what he has done."
Who are the Luxembourg Boxing Federation?
The organisation was set up in 1922, and is affiliated to the European Boxing Union.
Why was Luxembourg chosen?
Warren said it is regulated by the Luxembourg government, and was one of a handful of offers he had received to licence Chisora.
"Why Luxembourg? Why not? They are a member of the European Boxing Union and have been around for a long time," he said.
"I've had a number of offers, some from within Europe and some outside. It could be that Dereck goes into the ring with three or four licences from different organisations."
Why has the Luxembourg Boxing Federation agreed to the fight?
"They will be given a sanction fee for the big fight," Costello said. "One of the reasons why the sport is in such confusion worldwide is because there are so many different bodies funded by percentage of purses - which is why fights are sanctioned."
Are any other countries involved?
The fight is not being promoted directly by Frank Warren, but by BoxNation and a top German promoter, Sauerland Promotions - they promote some fights under the auspices of the Austrian Boxing Federation.
How will the British Boxing Board of Control feel about the news?
"This is a huge challenge for them," Costello said. "It is a dent to their authority and fundamentally undermines their control. There is little legally that can be done."
Why is this fight going ahead?
The pair brawled following Chisora's defeat by Klitschko in Munich. Warren had initially said he would not organise a fight between the two but now says he has changed his mind because Chisora's appeal was put back from May.
He was annoyed that Klitschko's brother Wladimir was in the Briton's dressing room before the fight and feels the BBBofC should have done something to stop it.
Will people watch it?
Costello said: "As much as many people will find it unedifying, there's a big enough audience for this to happen. I would expect most of the tickets to be sold. There is so much controversy, a back story and two heavyweights who are almost having a rematch. This will probably be the biggest fight in this country since
Ricky Hatton fought Juan Lazcano.
While some people won't like it, I think it will take off."
Is this a risky strategy for Warren?
"Frank Warren has been at or near the top of the game in this country for 30 years and wouldn't be doing this unless he thought everything could happen and he would emerge unscathed. He will have thought deeply about this and all the legal implications," Costello said.