WARNING: VIDEO CONTAINS STRONG LANGUAGE

Big-hearted Conor McGregor has flown a Youtube star to Las Vegas after his tribute song to the UFC star went viral ahead of his boxing match with Floyd Mayweather.

The video of Mick Konstantin's catchy tune has racked up nearly four million views on Facebook alone.

Speaking to MMA Fighting, McGregor said: "It’s one hell of a song! It’s a very catchy song. We actually reached out to the guy.

"We booked him a flight, him plus one, brought him over to the fight, got him tickets and put him up in a hotel.  I’ll meet him maybe after the fight!"

The song which is available on iTunes is raising money for Our Lady's Children's Hospital, Crumlin in Dublin.

Last night Mayweather tipped the scales at 149.5lbs, three and a half lighter than his Irish opponent and four and a half below the light-middleweight limit.

Glasgow Times:

McGregor is expected to be significantly heavier by the time the two fighters enter the ring, and he said of his undefeated opponent, who fights for the 50th time: "He's full of water: that's the worst shape I've ever seen him in.

"That's the worst shape I've seen in him. He looks out of shape; I'm going to breeze through him.

"I'm a professional; I make weight. It's about sacrifices, dedication, it's focus, I make it, and that's it. I've put in the work as everyone can tell. I'm ready.

"(I'll be) a lot bigger than him (on fight night). Pushing 170lbs.

"You'll never beat the Irish, and that's it. Las Vegas is ours now. I'll stop him in four. Let's see if he can take it."

Lyrics to There’s Only One Conor McGregor

A kid from Dublin with more than a dream

He knew one day he'd be the king of the UFC

With a group of fighting Irish not to be pushed over

Not here to take part they were here to take over

From the start John Kavanagh by his side

Whoever thought they'd be known worldwide

After 60g's baby and a contract to sign

Leaving his old life and the social welfare behind

After 2 years came the featherweight champion of the world

Conor said he'd make him look like a little girl

It only took ten seconds to show his talk wasn't cheap

As he connected with the left, and put ALDO TO SLEEP!

There's only one Conor McGregor, and there's no fighter better

And he's going to knock out Floyd Mayweather

So Floyd watch out cos the Irish are coming

You can talk all you want, buy you'll do nothin!

The lightweight belt was next in store

To do what no other fighter had ever done before

Became the first same time double champ in history

And took the chance to apologise to absolutely nobody

Came from working on a building site

To getting million dollar pay cheques from Dana White

And now his money, his cars and his clothes he flaunts

Cos the double champ does what the f**k he wants

Mayweather, your old and your small

And the truth is that you'll do feck all

Cos precision beats power and timing beats speed

"Why have you got a school bag Floyd you can't even read"

Well he dresses to kill, buys Lamborghinis at will

Can get inside your head like he was Dr. Phil

And if you call him out, have a good reason why

Or he'll turn around and say who the f**k is that guy

And on the 26th of August we're taking over Vegas

The Irish invasion you can't mistake us

Singing songs day and night ’til our voices are sore

Cos when one of us goes, we all go to war!!