Beauty

Zac Efron is showing plenty of skin for his new movie -- we've seen the photos -- but there is one body part he's not willing to put on camera ... his butt.

Zac continued filming "Dirty Grandpa" down in Georgia, and it looks like there's a naked motorcycle scene -- but for some reason Zac's a little ass-shy. A butt-double was photographed stepping in for Efron.

Based on pics ... you'd think Zac would be happy to flaunt his cheeks, but instead it was the double's butt in the spotlight.

Mariah Carey is unreal ... we got audio of her full dress rehearsal for her Vegas show which opens tonight, and she sounds as good as she did in 1990 when she hit #1 with "Vision of Love."

Mariah performed for more than an hour Monday night to a packed house at The Colosseum at Caesar's Palace, and you gotta hear it. She hits every high note and sounds flawless.

We got audio from someone in the audience ... filled with various people who work in Vegas-related businesses. We posted a minute-and-a-half and sampled 4 songs. Wait till you hear her hit the high notes in "Emotions."

As for the naysayers who claimed she wasn't rehearsing enough ... whatever she did was clearly enough.

It would be tough to punch and kick your brother-in-law when you're wearing ... whatever the hell Solange Knowles wore Monday night to the Met Gala.

Hard to believe -- but it's been a year since Beyonce's sister famously went ballistic and attacked Jay Z in an elevator ... during an after party for last year's gala.

Meanwhile, Bey stole the whole damn night when she showed up in a ridiculous sheer nude-colored dress.

Damned if she was gonna let Solange steal the headlines this year.

Traditional ... or edgy?

Safe ... or risky?

White shirt, black tie ... or crazy red stripe and a white tie?!

That was the fashion dichotomy between Derek Jeter and Dwyane Wade in NYC Monday night ... with one star pushing the envelope and the other one ... well, not.

Question is ... who looked better?

BTW -- same situation with Aaron Rodgers and Odell Beckham ... with the QB going the Jeter route ... and OB rockin' a crushed velvet purple jacket!

The Met Gala is where the biggest names in celebrity combine with the biggest names in fashion ... but it's also where Kim Kardashian's famous ass meets Jennifer Lopez's legendary backside.

KK acknowledged the moment by posting this homage to their posteriors ... snapped by none other than Kanye West.

There's no wrong answer, yet we have to ask ...

You don't have to give a crap about dancing ... to give a crap about Rumer Willis emerging as a major piece on "Dancing with the Stars" -- although you'd have to watch the damn show to know that.

As we've said ... she doesn't need the Mirrorball Trophy (but she'll probably get it) -- Rumer's already won the Now Everyone Knows I Have a Bangin' Body award.

Exhibit A: this outfit with the neckline down to her belly button, and the leg slit up to her ... ya know.

Oscar Del La Hoya is still a knockout!

Here's a 22-year-old version of "The Golden Boy" after a boxing workout in New York City back in 1995 (left) and 20 years later ... the now 42-year-old Olympic Gold Medalist at a press conference in Los Angeles earlier this year (right).

LeAnn Rimes is lucky she's famous ... because most people would be in serious trouble if they set off the fire alarm on an airplane, but she was able to joke about it.

The country music/reality TV star was on a flight to Los Angeles, when she took a bathroom break to freshen up. As she explains it: "Leave it up to me to set off the fire alarm in the airplane bathroom w/ @theDrybar dry shampoo #purecomedy #firsttimeforeverything."

Our photog was waiting for LeAnn when she landed, and she laughed off the whole thing -- although it sounds like the flight staff wasn't as amused ... at first, anyway.

Tim McGraw ... talk about country strong.

Guests at the Hotel Del Coronado near San Diego were stunned when a semi-exposed and hairless Tim put on a gun show before performing at his own show later that night.

The country star -- who turns 48 today -- credits his godly physique to the Paleo diet and CrossFit.

Kim Kardashian will support Bruce Jenner in any way she can during his transition ... except when it comes to the people who make HER look good.

KK was a guest Thursday night on "Jimmy Kimmel Live" and talked about how Bruce has been doing since last week's big interview.

Bruce specifically called out Kim during his Diane Sawyer interview ... saying she's been the most supportive of all his children. But Kim told Jimmy her help was limited to just her and not her "glam team."

Zac Efron apparently had an extra ticket to the gun show Wednesday afternoon ... and he took 71-year-old Robert De Niro along with him.

Are we in for another walk-off?

"Zoolander 2" is shaping up to be the king of cameos ... as Ben Stiller just revealed Justin Bieber will make an appearance in the flick.

Bieber has hinted he might be appearing, writing, "Working on something big right now in Europe. To learn more follow me on Fahlo. He is so hot right now."

The photo kind of lets the cat out of the bag.

No word on what Biebs will do in the cameo ... maybe he's a graduate of "The Derek Zoolander Center For Kids Who Can't Read Good And Wanna Learn To Do Other Stuff Good Too."

It's been a while since we've seen 75-year-old Tina Turner out and about ... and after seeing how good she's looking these days, we gotta ask ... why the hell isn't she out more???

Turner emerged Tuesday on the streets of Milan for a shopping trip with hubby Erwin Bach.

Private dancing keeps you young.

Russell Wilson is having one hell of an off-season ... he just walked in to the White House State dinner with Ciara on his arm .... and she's looking DAMN FINE!!!!!

Rumors had been swirling about the Seattle Seahawks QB secretly dating the R&B singer ... but now, it appears to be official -- with Wilson bringing her as his date for dinner with President Obama and the Prime Minister of Japan.

Before Ciara came into the picture, Wilson -- who divorced his wife last year -- was spotted out with Sports Illustrated Swimsuit Edition model Samantha Hoopes ... but clearly, she's out -- Ciara's in.

Mazel!

Zac Efron is a brief guy ... at least he was on the set of his new film "Dirty Grandpa."

Efron is filming down in Georgia on Tybee Island and Monday he appeared to be baring it all. No such luck, just nude colored undies.

Funny, we had him pegged as a boxer guy but we're pretty sure there's a lot of ladies (and guys) who don't mind undies this tight.

Big Ang is out and about and flaunting new blonde locks ... just a few weeks after undergoing a lifesaving operation to remove a cancerous tumor from her neck.

The "Mob Wives" star was looking good Saturday outside Teak restaurant in Red Bank, NJ, and even stopped to pose with a fan. We're guessing the neckerchief is there to cover any surgery scars -- in the most stylish way possible.

Sources close to Ang tell us she lightened up before the surgery ... because she felt like she just needed a change after getting the cancer diagnosis.

Work it, Ang.