Hot Vegas

Mariah Carey is taking her Vegas residency as seriously as anything in her career ... so say the people getting her ready for next week's kickoff.

Our Mariah sources say she will not have a repeat of Japan ... her voice is "on fire." We got this pic of her rehearsing over the weekend with her musical director, producer and other show-related people.

There's lots of voice protection stuff in the picture ... throat coat, tea, etc.

As for preparation, one of her people says, "She's been singing these 18 #1 hits for a very long time."

Her show starts next Wednesday.

Floyd Mayweather vs. Manny Pacquiao is the main event but even the under, under ... UNDER card has some big names -- in the little boxing world, anyway.

"Mini Pretty Boy Money" and "Mini Pacman" went at it in the MGM Grand lobby on Monday ... not far from the full-size ring the resort is using to promote Saturday's huge bout.

You gotta see the stare down between the fighters -- absolutely menacing ... said no one.

But get this ... the ultra flyweights will really fight on Saturday night at Beacher's Madhouse and tickets ain't cheap. For $1500 you get to see Floyd and Manny on closed circuit, and then after that ... Mini Money and Mini Pac will go at it live.

Evander Holyfield finally has a date to the Mayweather vs. Pacquiao fight ... a mystery fan who just dropped $40,100 for one of the most V.I.P. boxing experiences EVER.

The "Real Deal" was part of an INSANE package featured in an eBay auction -- where the lucky winner gets:

-- One ticket to the fight ... sitting with Evander
-- 1st class airfare to and from Las Vegas
-- "Deluxe" room accommodations at the MGM Grand
-- A fancy steak dinner with Evander before the fight
-- One year of products from Quest Nutrition

There's more ... the proceeds from the auction benefit the CharityVision organization -- which helps visually challenged people in developing nations.

The package received 81 total bids -- and people who bid more than $25k had to pre-qualify with an independent agency.

Mariah Carey was welcomed Monday to Caesars Palace in Las Vegas with a quiet, understated gathering of a few close friends ... jkjk ... it was a giant, over-the-top spectacle!

Carey begins her residency at The Colosseum next week, and arrived Monday in a pink convertible, white fur stole, and nude bodysuit -- Mimi wasn't hiding a thing. In fact, she showed off all her #1s with a parade of 18 trucks -- one for each hit song.

Mariah spoke a little -- maybe she's saving her voice -- but mostly she let her anti-Nick Cannon anthem "Infinity" do the talking during her queen-like entrance.

If her Vegas shows are this well-produced, Mariah will be worth the price of admission.

It must have looked like someone left Sisqo in the dryer too long -- until the 90s R&B star made a surprise appearance to do a duet with his little doppelgänger at Beacher's Madhouse.

At first, just Mini Sisqo got the crowd jumpin' Saturday night in Las Vegas with "Thong Song" -- and then out of nowhere the real deal singer jumped on stage and took over mic duties. The little guy managed to hold his own though ... while rocking a throwback headband. #respect

Turns out Mini Sisqo is multi-talented ... he also does a mean Mini Kanye.

Jarret Stoll had been raging in Vegas with several of his L.A. Kings teammates in the hours before the NHL star was busted for trying to bring a BUNCH of cocaine and molly to a pool party ... TMZ Sports has learned.

Multiple sources confirm ... the Vegas vacation was essentially an unofficial end-of-the-season celebration to unwind and party as a team.

As far as how many Kings were part of the festivities -- sources tell us there were more than a dozen people from the organization on hand ... many of whom continued to party in Vegas throughout the weekend even AFTER Stoll was arrested.

We know Drew Doughty and Martin Jones were part of the Vegas crew -- but they were NOT arrested or accused of any wrongdoing whatsoever. In fact, the only person who got into any trouble was Stoll.

We reached out to the players and the Kings organization -- but no one wanted to comment on this specific story.

Kourtney Kardashian celebrated her 36 birthday Saturday night in Vegas with boyfriend Scott Disick ... and he looks less than enthused.

The bash was thrown at 1OAK. There was a pretty big crowd, sans all the other Kardashians. Kim's at home in L.A., Kylie's at Coachella with Tyga and Kendall.

Khloe was busy Saturday night throwing a shindig for her new group messaging app called Regroupd.

The sheets were still warm when Britney Spears slipped into her Las Vegas pad -- because she didn't even wait 24 hours for Elton John to move out before moving back into the uber swank suite.

Sources close to the singers tell TMZ ... Brit is going to be living it up in the 8,000 sq. ft. paradise known as the Palazzo Suite at Rio while she's in Vegas. Elton lived there during his most recent Caesars Palace stint ... but we're told he moved out Tuesday night, and Brit was in by Wednesday morning.

The two have been trading off at the suite for some time now and Elton lived there while Brit was on her most recent hiatus. Britney has called the pad home for the last 13 months.

The THREE floor suite comes with 24-hour butler service, 2 jacuzzis, an elevator, and furniture on loan from 17 museums around the world. Sir Elton has standards.

10:45 AM PT -- It now sounds like the guy who said "fat bitch" is so far back there's no way Britney could have heard him. So the question ... what happened that pissed her off so much? Several sources who work on the show tell TMZ, they believe Britney was reacting to a comment someone made in the audience, but they don't know what was said.

Check out the video closely. It looks like the music may have started late ... so that's a possible trigger as well. But no one is saying definitively.

Britney Spears stood up for herself Wednesday night during her show, when someone in the audience apparently called her a "fat bitch."

A guy standing next to the mic says "fat bitch", and you can clearly hear Britney say ... "f***ing asshole."

It's interesting on several levels. Critics of her show say she walks through her performance like a robot, but this clip clearly shows Britney's antennas are up.

Plus, her mic was on ... during a song!!!

And she doesn't take crap from random people. Are you listening Sam Lutfi?

He can DEFINITELY afford tickets, but Floyd Mayweather says he WON'T be hitting up Jay Z's post-fight mega-party in Vegas -- there's another place he's already committed to be.

TMZ Sports spoke with Money at his media day workout at his gym near the Las Vegas strip Tuesday night ... when we pointed out all of the post-fight party options ... Chris Brown, Nicki Minaj, Snoop, Jay, etc.

By the way, VIP packages for Jay's shindig are on sale for up to $50k!!! Insane, but a drop in the bucket for Floyd.

Three 6 Mafia rapper Crunchy Black is a man who knows what he wants when it comes to drugs ... but according to cops he isn't too good at getting it.

Law enforcement sources tell TMZ the Oscar winner was roaming the streets of Vegas early Tuesday when he was stopped for walking into an intersection when the "do not cross" light was flashing.

It didn't take long for cops to discover meth.

According to the police report, Crunchy's response was hilariously incriminating. He said, "Oh damn. I was trying to buy that powder, not meth."

For bad measure the 'Three 6' rapper also had 2 warrants for his arrest. He was booked for possession and for providing a phony name. He's still in custody.

Crunchy has other problems. He's still a wanted man in Minnesota after allegedly beating his girlfriend in a hotel room.

A rep for Crunchy Black tells us the rapper wants to move forward with his life and will handle the charges in court. Some advice ... don't move forward when the "don't walk" sign is flashing.

Now that he's been booted from "Dancing with the Stars," NFL wannabe Michael Sam was looking to drown his sorrows in Las Vegas this weekend -- by kickin' it at the pool with Sammy Hagar.

The former Van Halen frontman and the former NFL player hung out at the Azure Luxury Pool at the Palazzo hotel ... where Sammy was trying to promote his new poolside bar.

Rapper YC -- aka Yung Chris -- just learned fidelity is a key part of marriage ... especially the night before your wedding.

YC and his GF of 5 years, Tia Anderson ... decided to elope at the end of March, and invited a handful of family and friends to join them at the Bellagio in Vegas. What they didn't plan on was the smokin' hot bartender.

YC's rep Kali Bowyer says Tia spotted YC -- best known for his hit, "Racks" -- getting handsy with a hotel bartender on Friday night ... and immediately pulled the plug on the Saturday ceremony.

YC's telling friends nothing happened with the drink-slinger, but admits it was heading in that direction. Not that it matters to Tia ... the damage was done.

As for the ring -- we're told Tia's keeping it. If YC's looking for ice ... try the bartender.

His name is Barry
He's got a ring on
And husband Garry's got one too
We all scratched and said "Who knew?"

Barry Manilow was belting out one of his many hits at the MGM Grand in Vegas with a shiny wedding ring on his finger.

The pic doesn't show it, but we're guessing he's excited that it's out he married his longtime manager Garry Kief last year.

Now we know who Barry can't smile without.

The weekend of the Mayweather vs. Pacquiao fight will be LEGENDARY for pimps, hos, marks, mark ass marks, trick ass marks, punk bitches and skip skap scallywags alike.

At least according to one of the most famous (and perhaps the most celebrated) pimp of all time ... Bishop Don "Magic" Juan.

The Bishop was hangin' at Berri's Cafe on Third in L.A. when he told us Sin City will be a virtual ho-asis on May 2nd ... because hos go where the money is.

"People are bringing hundreds of thousands [of dollars] just to throw away," Bishop says.

The competition for the hottest Mayweather/Pacquiao post-fight party is over ... cause Jay Z just announced he's getting in the game ... with V.I.P. tables running up to $50k-a-pop.

It's all going down at Marquee nightclub at the Cosmopolitan Hotel in Vegas -- just down the way from where Manny and Floyd will be facing off on May 2nd.

We spoke with party honchos who tell us they expect this to be the biggest after-party on the strip -- despite fierce competition from stars like Nicki Minaj, Chris Brown and 2 Chainz.

If you don't have $50k, don't worry ... there are cheaper options.

General admission tickets are $100 -- if you have a penis.

Tickets for females are significantly cheaper ... $30.

Gender equality -- it ain't for everybody.