Mayweather decides to go for a crazy wrestler look, with his face covered, apart from holes for his eyes and his mouth.

He enters the arena and is booed. This is a man who is the best boxer of a generation, a man who has won all 49 of his contests and he is booed in what will probably be the last fight of his career.

And here comes Conor McGregor. What a reception from the Irish fans. He raises both arms as he acknowledges his support.

Image source, Reuters

Conor McGregor has promised he will 'sleep' Mayweather inside two rounds, but it's been a very long time since the richest boxer in the world has touched the canvas.

You would have to go all the way back to Mayweather's first world title reign as WBC super-featherweight champion in 2001, when he fought Carlos Hernandez.

Mayweather's glove touched the canvas as he lost his balance, which he claims was a slip, but the referee still gave him a count.

And that's it, in an entire 49-fight career.

Don't forget rapper P Diddy (or to anyone who is old, Puff Daddy). Well, whoever he is, he's in the arena too.

Image source, Reuters

...as is basketball superstar LeBron James.

Image source, Reuters

'Iron' Mike Tyson is here...

Image source, Reuters

Before we go any further, a bit more celebrity spotting for you...

Luke Reddy
BBC Sport boxing reporter in Las Vegas

Moment of the night. Bruce Willis just walked past me and some guy shouts "hey McClane".

The Die Hard star looked as if to say, 'never heard that one.'

Image source, Reuters

Now this has to be a good sign. Here comes the national anthems, we can't have too long to wait. Conor McGregor stands in his dressing room, the jokes are over, the stare, an intense, about-to-do-some-damage stare is clearly visible.

Earlier on...

Floyd Mayweather's protege Gervonta Davis remains undefeated in 19 fights with an eighth round stoppage of Francisco Fonseca.

It ended in controversial fashion as the final blow appeared to show Davis illegally hitting Fonseca on the back of the head before he went down and didn't rise to the referee's count, but Davis disagrees.

"I hit him with a good left to the body before. He knew that he was hurt and that had no effect on the result," he said.

However, despite winning, the former IBF world champion will regret not making weight for the fight as he lost his title yesterday on the scales.

He added: "I made a mistake because I'm young and I'm growing so I apologise to everyone for not making weight for this fight. All the (fighters in the division) 130 to 135 (lbs) I'm coming back for my belt."

OnsideVIEW:#bbcboxing, external Can I grab you a cup of coffee??

We've got a few hungry people here. A few chocolate bars would be great, cheers.

Steve Bunce
BBC Radio 5 live boxing pundit in Las Vegas

There's no danger of them (Mayweather and McGregor) warming up, getting their gloves on and then being told they have to wait 45 minutes.

Everything will work according to what they've been told. They will be all right.

It's more the people who are generating the pay per view sales, they will start to panic.

Michael Page
MMA star for BBC Radio 5 live in Las Vegas

I don't think it'll do much to these guys, they are veterans in the game and used to being the main event.

They will get the information. They will be eager to get out and perform. It won't affect them.

Steve Bunce
BBC Radio 5 live boxing pundit in Las Vegas

They are going for 4.6m sales, that was the record set by Mayweather v Manny Pacquiao two years ago.

They have the technology to see how many people are waiting, registering to buy pay per view.

At $100 you don't need that many waiting to hit $1m. I hate to scare you, but there won't be a cut off.

Some more information coming up on these delays.

So how do you dress heading into the ring? Maybe, anything than like this.

BBC Sport app users may need to click the link to see Gervonta Davis's outfit in all its, er, glory.

We have a statement from broadcasters Showtime, who have explained why things are running late.

The statement says: "Due to high demand, we have reports of scattered outages from various cable and satellite provides and the online offering.

"We will delay the start of the main event slightly to allow for systems to get on track. We do not expect a lengthy delay."

No drama, we've been writing this stuff since 21:00 BST and we've got loads more in the tank.

Watch as BBC Sport's Richard Conway and Mike Costello met Floyd Mayweather and Conor McGregor in Las Vegas earlier in the week.

Originally, this fight was set to get going at 04:00 BST, but we are running later than expected, as the organisers wish to maximise the pay per view revenue.

We are not totally sure when the fight will be going on, but there are no more undercard fights so it won't be too long.

We said ultra smooth, and this is how Conor McGregor's son will be looking tonight, in the same suit (albeit much, much smaller) as his dad's.

BBC Sport app users may need to click on the link.

It then led to Verne Troyer, who plays the character of Mini Me in the Austin Powers films, to post this great tweet in response.

Image source, .