Anthony Joshua's fight against Carlos Takam will break a record set by Muhammad Ali back in 1978, as the pair fight in front of a record-smashing 78,000 within the closed Principality Stadium in Cardiff.
The previous record for an indoor boxing event was set by Ali and Leon Spinks in the New Orleans Superdome, when 63,315 fans turned up to see Ali's victory.
Joshua will be defending his heavyweight title at the biggest ever indoor boxing event, which was also the fastest-selling event the stadium has ever seen, according to organisers.
Promoter Eddie Hear said: "We've never seen anything like this in British boxing and we may never see anything like it again.
"This fight will be broadcast in over 160 countries worldwide."
Joshua is the heaviest he's ever been, weighing in at 18st 2lbs, while Takam is 16st 11lbs.
The British champ was initially placed against Kubrat Pulev, but the Croatian had to pull out due to an injury and Takam was called in as a replacement.
Despite only being announced for the fight 12 days ago, Joshua is not taking a win against Takam for granted.
The 28-year-old said: "I know what it's like to be a challenger. Believe it or not I still have the mindset of a challenger. I don't walk around with an ego just because I have a few belts on my shoulder.
"I know he has that mindset to find a way to win. If you keep on knocking on the door you find a way through. I just have to boot him out because he isn't coming through this door.
"I'm still developing. I think that's why people jump at the opportunity. If I trashed talked more I may be more feared. But my job is to break them down in the ring, strip them of confidence, strip them of desire and strip them of winning."
Takam seems more than aware of the massive opportunity this fight gives him, saying: "I am ready and going to give it all.
"This will change my life of course. Just in boxing, not the person I am."
The fight is set to be televised in over 150 countries, according to Hearn, who said: "I am astonished at the incredible numbers. He reaches out to every kind of genre, kids, women, middle-aged guys. He has time for all of them."
Featured Image Credit: PA