Here we go then with the co-main event.

First out is a very confident-looking Joseph Parker, bouncing and shadow boxing his way to the ring.

He fist bumps someone in a seat at the edge of crowd, which half felt he was covering for going the wrong way to the ring.

Image source, Matchroom

Image source, Getty Images

Joseph Parker and his team have been full of confidence in Riyadh, convinced they will cause the upset.

"I'm not here to get knocked out," Parker, 31, says. "Beat Wilder and the whole world is open."

For Wilder this is more than just a stepping stone. His plan is to dish "a little bit of payback" to Parker, blaming him for a unification contest, at a time when they were both champions, not happening.

"They never gave me the opportunity because I have a blessing and a curse in my right hand," he explains.

"Parker came to my fight, we talked about fighting and after I had a devastating knockout in my performance he ran from me.

"We never heard anything from him and next thing he's fighting another champion."

Image source, BBC Sport

Deontay Wilder has an incredible 42 knockouts in his 43 wins, will he add another one tonight or can Joseph Parker stop the Bronze Bomber?

Deontay Wilder, ever the showman, is being prepped for his ringwalk with a cloak and crown.

Let's hope he's learned lessons from the past and he's double checked its weight first...

Image source, Matchroom

George Groves
Former world champion on BBC Radio 5 Live

So it seems we are now just one successful night away from Anthony Joshua and Deontay Wilder finally getting it on next year - but they could have saved us all some stress by picking easier fights.

It is not out of the question that Joshua loses against Otto Wallin or Wilder loses to Joseph Parker - I'm not picking against either of them, but neither would be the biggest upset this year, or even this month.

In particular, Wallin is no walkover for Joshua and it is a very risky fight given what is at stake.

I am assuming it just came down to what the Saudis requested. I don't know who is making the matches but someone knows they need meaningful fights if they are paying so much money.

Ultimately, everyone is doing what they're told because the money is really good.

The media conference was announced and everyone flew in for it instantly. These people make stuff happen.

But don't get me wrong - although these are risky fights for both, they are certainly winnable fights too. If they can't get through these then Wilder and Joshua fighting each other isn't really of interest anyway.

• Read more of George Groves' exclusive BBC Sport column

Kal Sajad
BBC Sport at Kingdom Arena, Riyadh

Everybody is wondering whether Anthony Joshua v Deontay Wilder will be announced tonight.

We have heard of a two-fight deal and a date of 9 March in Riyadh. I also heard whispers 2 March could be a possibility. Some reports suggest both men have already signed a contract. Promoters have remained coy, neither confirming or denying the rumours.

The boxing world is jumping the gun a little bit. Otto Wallin and Joseph Parker are live contenders and a win for either man would not be the greatest shock in boxing. At the very least, it’s completely feasible for Wilder or Joshua to pick up an injury or cut in the fight.

But then again, the prospect of AJ and the Bronze Bomber scoring early knockout wins and then facing off in the ring is also wholly possible.

Deontay Wilder believes Anthony Joshua does not "have the heart" to fight him, with the former world heavyweight champions fighting on the same bill tonight.

New Zealand's Joseph Parker says "the whole world is open" if he wins his heavyweight fight with American Deontay Wilder.

Kal Sajad
BBC Sport at Kingdom Arena, Riyadh

Deontay Wilder has been a mixed bag in fight week. At times we’ve seen the confident, loud and exaggerated Wilder. The Bronze Bomber has screamed his catchphrase ‘Bomb Squad’ on demand and has promised to put Joseph Parker “to sleep”.

But when it comes to talks of a potential fight with Anthony Joshua, Wilder has – on the whole – been fairly respectful this week. Telling the media to get off AJ’s back. Then again, the week before he labelled the Briton as “mentally weak.”

A deal to fight Anthony Joshua appears close, but Deontay Wilder is also targeting the winner of Tyson Fury and Oleksandr Usyk, who contest the undisputed heavyweight world title in February.

"This next phase is all about unifying - I never had [that] opportunity," Wilder adds.

"The second time around will be even more beautiful than the first time around. I can guarantee you that.

"I keep it real. What I say is real. I don't shortcut nothing. When I'm speaking my piece I'm truthfully speaking and I say it how it is."

At Friday's weigh-in, Wilder, 38, towered over 31-year-old Joseph Parker but weighed in low at just 15st 3lb. New Zealand's Parker is 17st 1lb.

Image source, Getty Images

Deontay Wilder, arguably the hardest hitting heavyweight in history, has boxed fewer than three minutes in more than two years.

Yet the 'Bronze Bomber' remains one of the biggest draws in the sport, testament to his equaliser - a right hand which almost always spares ringside judges of a hard night's work.

"When people get dressed and go see a fight, they want to see a knockout. And that's what I give them," Wilder - who boasts a staggering 42 knockouts in 43 wins over a 15-year-career - tells BBC Sport.

"They know if they want to see a knockout, come to a Deontay Wilder fight. You're going to get explosive punches and a hell of a fight."

Having stopped Robert Helenius in the first round in October 2022 in his last fight, former WBC world champion Wilder takes on New Zealand's Joseph Parker.

Could we have the first undisputed light-heavyweight fight in the four-belt era?

Liverpool's Callum Smith challenges WBC, IBF and WBO light-heavyweight champion Artur Beterbiev on 13 January.

Matchroom chief Eddie Hearn, speaking to DAZN: "The undisputed fight is always the biggest fight in the division. Saudi want Bivol v Beterbiev here, but I believe Callum Smith will knock out Beterbiev and it will be Smith v Bivol."

Lyndon Arthur, speaking to DAZN: "I performed as good as I could with the time I had. I had four weeks. I did alright against pound-for-pound one of the best in the world. I believe Bivol will beat Beterbiev. He is a great fighter and I did what I could."

Dmitry Bivol, speaking to DAZN: "Lyndon was using a good jab. I'm glad that I got this fight at the end of the year and now I see my way to my goal of being undisputed."

First fight since hand operation: "I didn't push too much sometimes because I wasn't sure whether I had power. I looked at his eyes and he was ready for 12 rounds. For 13 months I wanted this fight."

On winning IBO title, which is not considered a major world title: "It's important. I didn't get anything from my opponent, now I have this belt."

On Artur Beterbiev v Callum Smith world title fight in January: "When I signed the contract for this fight, that was next."

Right, two fights to go - two huge fights with Deontay Wilder up first against Joseph Parker before Anthony Joshua faces Otto Wallin.

Don't forget you can listen to build up and live commentary on BBC Radio 5 live now.

Lyndon Arthur says he is proud of how he did against Dmitry Bivol and he certainly can be. He took this fight at short notice and took it the distance.

All three judges score it 120-107 in Dmitry Bivol's favour as he adds the IBO title to his WBA light-heavyweight world title.

Barry Jones
Former world champion on BBC Radio 5 Live

Those last four rounds for Lyndon Arthur were really hard for him, but he dug in. He could have done more and it's frustrating because he's such a good boxer.

And Arthur gets to hear the final bell. Both show each other mutual respect at the end, a good finish by Arthur but Bivol surely took every round there to defend his title.

Image source, Matchroom

Arthur is put up against the ropes and Bivol unloads. Arthur has just 20 seconds to try and hang on...