And we are seeing footage of Floyd Mayweather with his huge entourage arriving in the arena. He is super chilled out, headphones in, music on, dancing to the dressing room.

Not a man who is worried about potentially losing his professional unbeaten record in what would be arguably the biggest upset in sport ever.

His outfit is a piece of work as well. A tracksuit with his name written in big gold sparkly letters on the back. Snazzy, if you like that sort of thing.

Image source, Floyd Mayweather

Ricky Hatton is the only British fighter who knows what it is like to fight Floyd Mayweather, losing in the 10th round in their fight in December 2007.

The former two-weight world champion says Floyd Mayweather v Conor McGregor is "pure showbiz" - and says he is "a little bit disappointed" with how boxing has gone where these fights can now take place.

Watch the interview here.

Karoo Girl: Loving the hype! Supporting Conor McGregor for a win tonight.

Samab Ahmad: You call this boxing it is more of a circus. I lost respect for both sports. It is not USA vs Ireland. It is $ vs $.

British boxer Anthony Crolla believes UFC lightweight champion Conor McGregor should not be allowed to fight Floyd Mayweather in Las Vegas.

"It's absolutely crazy. It's a circus," former world lightweight champion Crolla told BBC Radio 5 live.

"It's almost like in Rocky III, when he fought Hulk Hogan. It comes down to money.

"Should a guy who has not had a professional fight be allowed to fight one of the greatest fighters ever? No."

The multi-million fight will be the most lucrative in boxing history.

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Luke Reddy
BBC Sport boxing reporter in Las Vegas

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There are some lovely lines in the official programme tonight. Some of those involved such as Dana White, Conor McGregor and Floyd Mayweather have drafted letters to fans which have been published.

Mayweather points out he has "broken the same records I once created." He writes: "Tonight is not like any other fight you have seen Floyd 'Money' Mayweather perform in. Tonight you will see me pour my blood, sweat and tears on this stage at the T-Mobile Arena in front of millions of fight fans."

McGregor's letter states his rival is a "legend of his sport for many years". He adds: "But I am the new generation, breaking down barriers built between mixed martial arts and boxing. I've said it before and I'll say it again before I take over boxing. I'm not here to take part, I'm here to take over."

Conor McGregor is already leading one battle, the one taking place on social media...

According to a PR agency, the Irishman has had 3,267,807 Twitter engagements since last Saturday up to earlier tonight compared to Floyd Mayweather's 1,357,115.

#Winning

The Irish will be in full voice for their man Conor McGregor tonight including some of the country's other fighters.

Commonwealth super-flyweight champion Jamie Conlan is out in Vegas with his brother Michael, also a professional, and former world champion Carl Frampton.

He filmed this from tonight's venue. Listen to that noise!

Luke Reddy
BBC Sport boxing reporter in Las Vegas

Image source, .

Just bumped into WBA featherweight king Leo Santa Cruz. He has his family with him - a big group - and was clutching about 20 tickets.

A photo, a fist bump and I guess with no surprise, he tells me he's picking Floyd.

Image source, Getty Images

So what can other sports learn from Conor McGregor's pre-fight exploits? A lot, according to golfer Rory McIlroy.

"All I've done is follow the build up to this thing," said the Northern Irishman. "Now that I'm off Twitter and social media, all I do is watch YouTube videos of Conor McGregor.

"I'm intrigued. He talks a good game. If you just listen to his press conferences and what he says, you would think that this guy, he's the one with the 50-0 boxing record. It's amazing. I'm a big admirer of him.

"He talks about visualisation and the law of attraction and all this stuff that he believes in and he vocalises it, and has the courage to say what he thinks. I'm a believer in that stuff, and I'm a big advocate of that.

"And some of the stuff he does wouldn't be my cup of tea, but he believes 100% in himself and he believes he's going to go out there on Saturday night and shock the world."

Luke Reddy
BBC Sport boxing reporter in Las Vegas

Image source, .

I've ventured up into parts of the arena where the air is thin to get a feel for what people are getting for their money up here.

It still looks fantastic as a venue but it would be hard to see the intricacies of punches from here. Still, the atmosphere can't be taken away so here's hoping everyone leaves feeling they've had value.

That would be a result for boxing and the UFC.

Earlier on tonight, Britain's Savannah Marshall won her first professional super-middleweight fight under Mayweather's promotional company with a unanimous points win over Sydney LeBlanc, with all three judges giving her the verdict by 40-36 margins.

The former amateur world champion, 26, thought about quitting the sport after returning from the Rio Olympics without a medal.

However, a friend of one of her former GB team mates dropped her name to Mayweather in a chance meeting and that led to her first professional fight on the biggest of stages.

"This gave me a mega switch in mindset," the Hartlepool fighter told BBC Sport before the fight.

"I felt like I didn't have the drive in me any more. Then, out of the blue, I get offered the deal of my dreams. I thought this is my chance and this is my time to be reborn."

Image source, Getty Images

Max Burns‏: Of course McGregor will win. Just to keep up with nonsensical events happening this year.

CF: Boxers are masters of balance. Floyd Mayweather has already beaten fighters who punch twice as hard as Conor McGregor & who have better balance. Floyd Mayweather wins on points.

Ben Pathe: To paraphrase Don King, the chances of a complete novice boxer beating a hall of famer are slim and none and slim's out of town.

Image source, Getty Images

Former X Factor contestants Olly Murs and James Arthur are still singing from the same hymn sheet.

Tonight it reads Floyd Mayweather v Conor McGregor.

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Luke Reddy
BBC Sport boxing reporter in Las Vegas

Image source, .

Sean Hannan and his dad Duane are in Las Vegas from Arlington, Texas.

The nine-year-old is a huge Conor McGregor fan and is adamant he'll win tonight.

His dad tells me he's been buzzing with excitement since tickets were confirmed a few weeks ago and when I find them they are lurking by a door looking for the chance to grab a few celebrity snaps.

Sean looks a bit of a celeb himself, gloved up and ready for action. His dad says with a laugh: "Sean plays lacrosse, this kid likes to hit people."

Let's hear now from some of the fans who are in Las Vegas and the public are split over who will come out on top in the ring.

The fans are heading into the arena, well some of them are anyway.

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The constant chatter from both camps seems to have been endless in the build-up to tonight's fight, now Floyd Mayweather has said it all means nothing.

Image source, Getty Images

Luke Reddy
BBC Sport boxing reporter in Las Vegas

Image source, .

It's a different level heat today. Forget the fight inside this 20,000 seat T-Mobile Arena, there is a scrum for shade outside. Not a cloud to be seen and the concrete under the feet sizzles.

Looking around I'd say a safe estimation is around 15 McGregor fans for every Mayweather one.

Las Vegas, the fight capital of the world, is certainly one unique and incredible place. Have a little glimpse of the setting for this fight with this video from our Instagram account.

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Remember, our vote is still up and running and we are asking you to predict what will happen tonight.

You will find the vote at the top of this page or via the 'vote' tab on mobile pages. The vote closes at 3.15 BST.