UFC

51-year-old Michael Irvin says he's itchin' for a fight -- a real MMA match -- telling TMZ Sports, "I would whoop somebody up!"

Mayweather's rep says, "The reason Floyd called Conor the F word is because Conor called Floyd a monkey. Floyd has nothing against gays or lesbians at all ... Floyd has them on his staff. Floyd has nothing but the utmost respect for gays and lesbians."

We're told the monkey comment allegedly happened off mic when Conor was storming around the stage and hyping up the crowd.

Floyd Mayweather crossed the line -- much like Conor McGregor did -- by calling him a "fa***t" during their London news conference.

The fighters were in the middle of wrapping up their world tour to promote their upcoming boxing match, and when Floyd grabbed the mic he started ripping into Conor ... calling him a string of names, including the homophobic slur.

Conor didn't react, but the crowd certainly did ... and it wasn't good.

Remember, a few days ago ... Conor told Floyd ... "Dance for me, boy!" He was, rightfully, taken to task for spewing a racist term to an African-American man.

Looks like it's Floyd's turn to feel the heat.

If you're gonna pick a fight with a hockey player, STAY AWAY FROM BRIAN MCGRATTAN ... so says Calgary Flames captain Mark Giordano.

We were talking to Mark about which hockey player would have the best shot at success in the UFC -- and without hesitation, Giordano brought up the legendary enforcer.

"I've never seen him lose a fight," Mark explained.

McGrattan -- 6'4", 235 lbs -- had a helluva fight record during his time in the NHL ... and is said to have not lost a single scrap during the 2013-2014 season despite playing in 76 games.

Here are some highlights. Enjoy the violence.

Jon Jones says he's not the only superstar with a taste for cocaine -- saying he knows for a fact that "some of the greatest athletes in the country" like to ride the blow train to snooter town.

The UFC superstar opened up about his well-documented coke use to Bleacher Report ... saying, "As far as me doing coke before a fight, that's not me trying to be a bad guy. That's me frickin' doing a bump -- you know, at a party."

"The truth of the matter is, you'd be surprised how many people have done coke. I've been around some of the greatest athletes in the country. Athletes with a lot bigger names than me do coke. But people don't talk about it."

Jones says the drug helps him have a good time -- saying, "If you can afford to smoke a little weed, and do a little coke, and still win world titles, who's to tell you you can't?"

"I understand these things are illegal. And once you get caught doing it, it's humiliating. But at the same time, I'm not an addict or anything like that. You don't see me walking around weighing fucking 100 pounds with my teeth rotting out and scabs all over my face."

It's not the first time Jon's been open about how much he likes coke -- he said the weekend he did blow and then beat Daniel Cormier was one of the best times of his life.

How does Floyd Mayweather feel about Conor McGregor calling him a "boy" twice? No offense taken.

In fact, Floyd actually tries to turn it into a joke -- "We all know there's only 2 types of boys -- a white boy and a cowboy -- and I'm neither."

TBE landed in NYC on Wednesday night, so we had to ask him about the outrage over Conor's racial comments at the 2 media events.

"Racism still exists but you know, I try to take something negative and turn it into something positive," Mayweather told us.

"A lot of people say that Conor McGregor is racist but I don't worry about that."

When asked specifically if he's upset with Conor over the comments, Floyd said he's not -- explaining, "It is what it is. He's entitled to feel how he wants to feel."

"I just want to stay in my zone and stay focused."

Tony Ferguson has a loud, finger-waggin' message for Conor McGregor ...

I'LL SEE YOU AFTER FLOYD, SON!!

We got T-Ferg leaving the first Mayweather-McGregor press conference at Staples Center Tuesday ... and the UFC lightweight contender wasted no time telling Conor -- the UFC lightweight champ -- what's up.

That said, Ferguson -- whose next fight isn't booked -- is open to other matchups ... like one with Justin Gaethje -- who dropped one of the most violent/awesome UFC debuts EVER last week.

"If he wants his a** kicked we'll handle that," Tony told TMZ Sports.

Dana White says he got a call from Donald Trump's camp about the McGregor vs. Mayweather fight -- but says POTUS likely won't attend because he feels like he "ruins events."

Of course, Dana and Donald are longtime friends (Dana spoke at the RNC) -- and White has previously told us Trump has an open invitation to attend any UFC event.

So, we asked if Trump would be at T-Mobile Arena on August 26 and White replied -- "Funny you say that. They called me yesterday."

White says Donald is 100% interested in the fight but feels he'd be too big of a distraction to attend in person.

"He feels like he'll ruin events," White said ... "Secret Service is going to have to go through the place, shut down streets and create crazy traffic."

Two things you don't say to black men in America ...

1) "Dance for Me"

2) "Boy"

Conor McGregor said BOTH of those things to Floyd Mayweather at the big fight news conference in L.A. and people are pissed.

The reaction on social media was swift with FS1's Chris Broussard tweeting, "'Dance for me, boy!' Ohh, ohh. Does he know what he just said?"

Not the first time Conor's gone racial to hype a fight -- he famously called Nate Diaz a "cholo gangster" before UFC 196.

Valentina Shevchenko is callin' B.S. on the reason behind Amanda Nunes' UFC 213 title fight withdrawal ... telling TMZ Sports she's "not believing 100%" that Nunes pulled out over health issues.

We spoke with Bullet about Nunes pulling out due to chronic sinusitis ... and Shevchenko says she doesn't believe the excuse because Lioness seemed perfectly healthy the week leading up to the fight.

As for why Nunes would make up the claim, Shevchenko speculates the withdrawal happened because Nunes was "feeling (her) energy" and wanted to reschedule the fight to throw off her rhythm.

Demi Lovato says Conor McGregor is straight LOCO ... and his insanity is what gives him a legit shot to shock Floyd Mayweather.

"Conor's crazy! And sometimes you can't beat crazy," Demi told TMZ Sports outside Break Room 86 in L.A.'s K-Town while promoting her new single "Sorry Not Sorry."

Demi's a HUUUUGE fight fan -- she's been training at Jay Glazer's Unbreakable Gym in L.A. with some of the top fighters in the world ... and Jay says she's no joke. We've seen video. He's right.

But when it comes to the Floyd, Conor thing -- Demi says she's siding with the Irishman ... explaining that a McGregor victory would be massive for the sport she loves.

Hail to the chief ... Conor McGregor!?

During Conor's insanely expensive Rodeo Drive shopping spree in Bev Hills on Monday, we asked the Irish superstar if he would be inviting the President of Ireland to sit ringside at the Mayweather fight.

His response is classic ... "I am the President of Ireland. He's fighting that night!"

Conor is undoubtedly one of the most Irish men alive -- in fact, there was a movement to honor McGregor last year by putting his face on official Irish money.

The UFC's most violent newcomer Justin Gaethje says he KNOWS a superfight with Conor McGregor is coming ... and tells TMZ Sports he'll beat the Irishman or die trying.

The undefeated Gaethje made a helluva statement in his UFC debut last week -- stopping Michael Johnson in one of the most brutal/awesome fights ever.

After the brawl, Gaethje called out Tony Ferguson -- and if he can get through Tony, it seems Conor McGregor could be waiting for him on the other side.

Gaethje told the guys on the TMZ Sports TV show (airs tonight on FS1) -- "That's what I'm here for ... don't worry guys, you'll get to see it."

You gotta listen to Gaethje explain his fight mentality -- dude's no joke.

Joanna Jedrzejczyk says she was so serious about stepping in for Amanda Nunes and fighting Valentina Shevchenko this weekend, she went to the gym on Saturday to get her body ready for the fight.

Joanna -- who Dana White described as a straight-up "gangster" -- explained the whole thing to TMZ Sports ... telling us she "really believed it was going to happen."

As we previously reported, Nunes bowed out of the UFC 213 fight on Saturday -- and Joanna offered to take her place ... despite the fact the fight was happening at 135 pounds and Joanna typically fights at 115.

Nate Diaz is firing shots at Conor McGregor and Dana White -- mocking the UFC duo on social media while proclaiming HIMSELF the real champ.

"There's 1 boss here," Diaz wrote under a picture of him busting out the Stockton Slap on both guys.

That's not all ... Nate also ripped into the photo Conor and Dana took together on Sunday after landing in L.A. for their Mayweather fight media tour.

"Little bitches," Diaz wrote ... "Got your ass beat. You lost bitch. Im the champ..."

Diaz hasn't stepped inside the Octagon since losing to McGregor in their rematch at UFC 202 back in August 2016.

White has told TMZ Sports he TRIED to make deals with Nate and his bro, Nick Diaz, to book them in other events ... but they flat-out refused every offer the UFC made.

Neither Dana nor Conor have responded to Diaz's comments -- yet -- but with the Mayweather media tour launching Tuesday, you can bet they'll have some thoughts on this dude.

UFC star Max Holloway is calling for a tag team match -- a 2-on-1 meg-brawl with Cub Swanson and Frankie Edgar ... and let's be honest, THAT SOUNDS AWESOME!!!

TMZ Sports spoke with Holloway about the next man on his hit list -- and he told us he's ready to fight both dudes ... even if it's at the same time.

Yeah, we know it ain't gonna happen -- but we can dream, right?

Amanda Nunes pulled out of her UFC 213 fight because she was dealing with a chronic condition that didn't allow her to breathe properly ... according to the brawler herself.

Amanda posted a statement Sunday explaining her sudden withdrawal from her main event fight against Valentina Shevchenko, saying she suffers from chronic sinusitis.

She goes on to explain that she's fought with the condition before, but couldn't soldier on this time because she felt off balance and couldn't breathe at the official weigh-in. She also says UFC docs cleared her based on blood and dehydration tests ... but a CT scan later found mucus build-up in her sinuses.

As we reported ... Amanda pulled out of UFC 213 last minute Saturday, only hours before her title match. She told UFC officials she did not feel well enough to step in the Octagon.