Celebrity Butts

Justin Bieber has the verde light to return to the Mayan ruins in Tulum, Mexico as long as he "behaves well," or as we say in this country ... don't act like a jerk!

The director for the National Institute of Anthropology and History tells TMZ, Bieber is welcome back -- and doesn't even have to apologize for disrespecting the sacred ground by drinking beer and mooning the tourists.

Kylie Jenner strategically used a Louis Vuitton purse to shield the goods, but the stairway to the gym became a stairway to heaven.

Here's what's not a stretch ... she looks hot.

Can't say we blame Jason Statham.

Best autocorrect ever?

Dictionary.com defines "lardass" as ... "a person having unusually large buttocks."

Just sayin' ...

John Stamos pulled a Kim Kardashian and flashed his bare ass in a photo spread for Paper magazine.

Everywhere you look ... there's his ass.

Harry Styles knows when you're onstage you're supposed to give performers a hand ... which may be why he grabbed Jimmy Kimmel's ass.

Harry and the rest of One Direction were guests on Kimmel's show Thursday and it all looked kosher from the front. What viewers didn't see was the ass grab from behind.

The performance was pretty epic BTW ... Hollywood Blvd was shut down for all the 1D fans ... one of whom snapped the butt pic.

Looks like Kimmel's reflexes kicked in pretty quick ... he kept a straight face.

Laura Govan is taking a stand for the MILFs of America ... saying that people hating on Scottie Pippen's wife Larsa need to fall back ... and embrace the wonder of well-aged butt cakes.

Govan was out in Calabasas when we asked about the daisy dukes that shook up Beverly Hills this week ... the super skimpy jean shorts that Larsa was wearing while out shopping with Kim K ... and her kid.

Laura knows all about MILFtroversy ... she recently got in a little hot water on Instagram over a sexy picture of her cooking in the kitchen ... with her son as the sous chef.

You gotta see Laura hit back at the haters ... with her logic being, as long as Scottie likes what he sees ... Larsa should be all systems go to show the world.

We agree ... don't stop, Larsa.

Kim Kardashian is inspiring a whole generation of models ... to get pearl necklaces and flash their asses -- and Abigail Ratchford is the latest.

Ratchford is in the middle of shooting pics for her 2016 calendar -- and at least one month of the year will be an homage to Kim's famous "Break the Internet" pose. Sources connected with the shoot tell us Abigail is doing her take on several famous sexy photos.

We're told there will be at least one topless shot (in body paint), but NO full frontal. There's always 2017, fellas.

You know what they say about butt naked imitation. It's awesome.

Scottie Pippen's wife definitely tried to step up her fashion game for a shopping trip with Kim Kardashian yesterday -- revealing some serious butt cheek in a pair of tiny Daisy Dukes.

Larsa Pippen went buns out in Bev Hills with Kim and Jonathan Cheban ... and while she definitely looked hot, some people are saying she pushed it too far, considering her 8-year-old daughter was in tow.

Suzy Cortez was just crowned the new Miss Bumbum Brazil ... which totally made sense as she turned to walk away.

Sometimes, in the pageant world, it pays to bring up the rear.

Karrueche Tran is the prototype of post-rapper breakup success ... which is why Rick Ross' ex Lira Galore has reached out to Tran's camp for an instruction manual.

Sources close to Lira tell us she met with Karrueche's manager, Jacob York, this week in Atlanta to see if he could provide career guidance. Lira -- whose engagement with Ross ended last week -- was impressed with how Karrueche remained relevant after her breakup with Chris Brown.

Lira's got plenty of modeling under her belt, but what she really wants to do is act. Karrueche has made the transition, acting in "The Bay" and "Vanity."

Here's a free tip ... keep your body hot and ass cheeks exposed. Take it from Karrueche.

Jennifer Lopez busted out her own version of 'Blue Steel' and even Mugatu's hairdo for her latest concert, because ... there's more to life than being really, really, ridiculously good looking.

Of course, J Lo also showed off her famous 46-year-old asset during Wednesday night's Madison Square Garden gig. Props to the designer of that super low-cut bodysuit.

Jennifer's so hot right now she could take a crap, wrap it in tinfoil, put a couple fish hooks on it and sell it to Queen Elizabeth as earrings.

Right, "Zoolander" fans?

Samantha Hoopes returned to the spot where she committed what some people call a crime, and others call a blessing from God -- and this time she was showing off way more skin!

The S.I. swimsuit model stirred an uproar inside Earth Bar in West Hollywood on Tuesday ... because she was wearing the tiniest of booty shorts. Well, she went back Wednesday, and lo and behold (seriously, behold) -- she arrived in lingerie.

Samantha told us, "On the way in some other girl's taking a picture of my ass. Another girl's like where's your pants?" However, you gotta see the guy in our video watching from his car -- he is NOT offended, at all!

Earlier, on TMZ Live, she dropped this pearl of ass-wisdom: "No one wants a finger in my butt."

Umm ... watch, she explains.

Kate Upton banged out a set of squats during a workout in West Hollywood with her personal trainer, who kept a watchful eye on ... her form.

Yes, he's actually getting paid to do this.

Justin Bieber's lawyers are barking about three nude pics taken of him on vacation in Bora Bora, but we know Justin isn't all that pissed because the shots show just how ... GIFTED he is.

Multiple sources close to Bieber tell TMZ he was upset paparazzi, armed with telephoto lenses, snapped the photos of him butt (and other parts) naked frolicking with Jayde Pierce. We're told he thought it was a total invasion of his privacy.

We saw it the same way, and decided NOT to post the images. But our sources say Justin's anger faded when the pics went viral ... for one seemingly larger than average reason: Bieber's a really big deal, and we're told he's happy the world knows it now.

As we reported, JB's lawyers threatened media outlets that published the pics. We're told his legal team was just doing its job ... sending the message that Justin's not okay with the violation.

But reality is, there's almost zero chance Justin sues ... 'cause as they say, size matters.

French Montana has an interesting theory ... this pic she posted on her website, khloewithak.com, could be a more powerful sales pitch for Nike than the company's potential new 3D printer.

We got French leaving Nice Guy in West Hollywood Wednesday when we asked whether Khloe Kardashian would be effective in pushing a proposed product, which would allow consumers to use a 3D printer to make shoes.

There's a lot of subtext ... French says his affection for his former GF is strong. But he's also embracing a product which is now the archrival of Adidas, the company that just hired new boyfriend James Harden as its pitchman.

Let's get real ... who notices the shoes?