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As mentioned, we've got live commentary of the Joshua-Usyk fight from 22:00 BST.

Before then, here's a clip from the 5 Live Boxing podcast, with Dillian Whyte's opinion on Usyk.

Coral Barry
BBC Sport combat sports editor in London

Image source, Getty Images

Oleksandr Usyk first laid eyes on Anthony Joshua 10 years ago. It was 2011 and Usyk was in the crowd to watch Joshua compete at the World Championships in Azerbaijan.

Joshua was 21 and shocked everyone by reaching the final, where he was beaten by Mahammadrasul Majidov.

Usyk says he knew then Joshua would be an Olympic champion and the pair have been on a collision course ever since. They both turned pro in 2013 and both became unified champions of their respective divisions.

• Read more of our profile on Oleksandr Usyk here

Image source, Getty Images

Well, yes. But this is boxing after all.

There has not been an undisputed heavyweight champion since Britain's Lennox Lewis held all the belts in 2000 and there was hope that Joshua would face fellow Briton Fury, the WBC title holder, this summer.

Talks between the camps had been ongoing and a fight between them was expected to be announced for 14 August in Saudi Arabia. However, those hopes were dashed when an arbitration hearing ruled that Fury was contractually obliged to fight American Deontay Wilder again.

Fury and Wilder will be fighting for a third time on 9 October in Las Vegas after their first meeting ended in a controversial draw in December 2018 before Fury won the rematch in February 2020.

"Do I want Joshua to win? Definitely," said Fury this week. "It doesn't make much sense me beating Usyk up. If Usyk does win he will cost us a few quid."

Joshua's promoter Eddie Hearn said he would be 'shocked' if a fight between the two Britons did not happen, while Frank Warren, Fury's co-promoter, said the bout would take place if both Joshua and Fury won their fights.

Coral Barry
BBC Sport combat sports editor in London

Lenin Castillo is in hospital and was conscious when getting into the ambulance.

It was hard to watch at ringside when Callum Smith floored Castillo with a heavy right. Castillo's legs were shaking when he was down and the medical team immediately jumped in the ring to help.

Taken off on a stretcher to big applause, but Matchroom says the 33-year-old went to hospital as a precautionary measure.

Campbell Hatton told Sky Sports Box Office: "I'm not happy with my performance at all to be honest, I'm a lot better than that. It was a difficult occasion and I was under a lot of pressure. The opponent was a lot better than anyone I have faced before, so there are positives and definitely negatives.

"He did a lot of flashy stuff and showboating, and it isn't something many of my opponents have done before and it wound me up a bit, but it's all learning."

"I'm already a lot better than I shown there, but onto the next one. Six rounds is still the best thing for me. Nerves and a bit of frustration burnt a lot of energy there. Next time, I will be better because I will learn from my mistakes."

Referee Marcus McDonnell gives it to Campbell Hatton by a 58-57 margin, meaning the Englishman moves to four wins from four fights.

We go to the referee's card after a frantic last round by both Campbell Hatton and Sonni Martinez of Uruguay.

It was the first six-rounder of Hatton's career, but he may well have just suffered his first defeat after three wins, but it's a contest he will have learned a lot from.

This is what promoter Eddie Hearn said on Twitter...

Earlier tonight, former world super-middleweight world champion Callum Smith gained a second-round win in his first fight at light-heavyweight.

Smith beat Lenin Castillo of the Dominican Republic by brutal knockout in round two.

Castillo immediately received attention from the medical staff on site, and left the ring on a stretcher.

He has been taken to a local hospital as a precaution. Sky are reporting that Castillo was conscious when taken to hospital and is now talking.

But it's a stark reminder of the bravery everyone exhibits when they step through the ropes, the dangers of the sport, but also the expert medical attention on hand. When we get an update on Castillo's condition we will let you know further.

Image source, Matchroom Boxing

Matthew Hatton had a great career in the ring, winning the European welterweight title and fighting for a light-middleweight world title.

Now he's on the other side of the ropes and full of pride as nephew Campbell Hatton is in his fourth pro fight after wins in his first three.

Hatton is in the fourth of a scheduled six rounds and he has got his hands full with tricky opponent Sonni Martinez.

The Uruguayan is landing with some solid work to the Hatton body and the 20-year-old Englishman needs a good last two rounds to get his arm raised here.

Image source, Matchroom Boxing

Recently, Campbell Hatton spoke to BBC Sport and said he has been surprised by how hard it is being a professional boxer and admits his debut was a bit of a "shock".

Campbell Hatton, the son of former two-weight world champion Ricky, has big shoes to fill but has won all three of his professional fights so far.

He is currently in action against Sonni Martinez, from Uruguay, who has two wins and four losses to his name.

Here's the face-off on Thursday...

What do you do on the night of a big fight? Well, for Anthony Joshua it's a trip to the barbers.

Will he cut Usyk down to size later on?

It's a sold out crowd at Tottenham Hotspur Stadium and it's an incredible arena.

This is how it looked on Thursday...

...and this is how it looked earlier today.

• Anthony Joshua (Great Britain) v Oleksandr Usyk (Ukraine) - WBA, WBO, IBF and IBO world heavyweight championships
• Lawrence Okolie (Great Britain) v Dilan Prasovic (Montenegro) - WBO world cruiserweight championship
• Campbell Hatton (Great Britain) v Sonni Martinez (Uruguay) 6x3 mins lightweight contest.

Hello and welcome along to BBC Sport's coverage of Anthony Joshua versus Oleksandr Usyk with the WBA, WBO, IBF and IBO world heavyweight titles up for grabs.

I'm Michael Emons and it is my pleasure to be talking you through all the action tonight.

We've got BBC Radio 5 Live commentary of the big fight from 22:00 BST in this page as well so get comfortable.

There's always something special about an Anthony Joshua world title fight.

He faces a fighter in Oleksandr Usyk who could well be the toughest test of his career, with Joshua knowing that a defeat would wreck his hopes of becoming an undisputed heavyweight champion.

We've also got 67,000 fans watching on for the biggest attendance at a British boxing event in three years.

Big-time boxing is back.

Image source, Getty Images