Stars In Heat

After only 16 days since her 18th birthday … Kendall Jenner decided to give the world a glimpse of her nipples … leaving everyone wondering ... what took so long?

Now here's the question ... does it all end with nipples, or will Kendall walk the path forged by her older sister, with the helping **** of Ray J?

And while we're at it ... we gotta ask ...

Here's Kate Upton ... basically naked ... with some strategically placed body paint.

You're welcome.

Kate got all painted up for a Sports Illustrated photo shoot -- in the footage, Kate's trying to recreate one of the mag's most famous Swimsuit Edition covers.

We think she nailed it.

"I definitely feel naked," Kate said during the shoot ... "Because I am."

Kate said the artists took a particularly long time to paint on the necklace on her boob area ... yeah, can't imagine why.

Justin Bieber is kicking himself right now ... because ex-girlfriend Selena Gomez and her perfect 21-year-old ass just hit Miami Beach in this bikini.

Beats stripper ass any day of the week.

Kim Kardashian started an ass-selfie trend ... 'cause after she shared her bikini-wedgie with the world ... ANOTHER wanna-butt celeb is following suit.

This time, the chick showing off her donk is Mercedes "MJ" Javid from "Shahs of Sunset."

It's definitely a change of pace from Kim ... and pro surfer Anastasia Ashley, who beat MJ to the punch with a butt-selfie last week.

Butt-selfies -- sometimes they're not all they're cracked up to be.

Here's Rihanna ... bent over a pole while wearing a tiny bikini ... in a series of hot poolside photos she just took while hanging out in Greece.

There's not really much more to say ... so, we'll just go with "Ef̱charistó̱" ... which, we're told, means "thank you" in Greek.

She's been naked for Playboy ... and donned itsy-bitsy bikinis for Sports Illustrated ... so it's no wonder Stephanie Seymour wasn't shy when it came to trying on lingerie in Italy yesterday.

The 45-year-old model grabbed some racy outfits while shopping at Agent Provocateur in Milan with her 66-year-old husband Peter Brant ... and tried them on right in front of the store window. It was awesome.

FYI -- Peter Brant is a paper mogul who happens to be a frickin' BILLIONAIRE!!!

So, good for him ... and good for her.

This hot piece of model ass belongs to Nikki Ferrell ... one of the chicks gunning to bang new "Bachelor" Juan Pablo Galavis ... and from the looks of things, she's a frontrunner.

Nikki (according to various reports) is a 26-year-old model from Kansas City ... who was spotted with the former pro soccer player in Miami this weekend.

Galavis appeared on "The Bachelorette" last season, but didn't crack the final 5.

Sometimes, ya gotta lose to win.

39-year-old Kate Moss isn't holding back before her big Playboy spread in January, removing her bikini top on the beach in Jamaica yesterday -- and she doesn't look half bad.

FYI, Moss will be gracing the cover of Playboy's 60th anniversary issue ... the same month she turns 40.

Jamaican us crazy.

With his NFL career seemingly over, former pro quarterback Tim Tebow hit the beach in Hawaii this weekend ... without his shirt.

Tebow was spotted being oiled up by a woman ... but fear not, his virginity is safe -- the woman is his sister Katie.

There was a buzz that Tebow had a shot with the pathetic Jacksonville Jaguars, but when we asked Jags owner Shahid Kahn about it last week, the guy just laughed it off.

So now, Tebow is focusing on more important things ... his tan.

Days after being officially renamed to the USA national team, soccer goddesses Alex Morgan and Sydney Leroux celebrated by hitting the beaches in Hawaii this weekend ... in very tiny bikinis.

The Women's World Cup tournament is still 2 years away, but qualifiers begin in Fall 2014 ... and the team is scheduled to take on Australia and New Zealand in some friendly matches later this month.

Enjoy the free time while ya got it.

Pam Anderson ain't exactly shy about public nudity ... so when the opportunity came up for the 46-year-old to go top down at a topless beach in France ... out came the gals.

Pam was with her BF Rick Salomon -- and the two were spotted romping around the beaches in Biarritz, France yesterday like two topless teenagers.

Fun Fact -- Biarritz is the birthplace of famed chemist Ernest Fourneau -- who played a key role in the development of chemotherapy as a way to combat cancer.

... and now you know.

Question: If you were thiiiiis close to being paralyzed after fracturing your neck in a freak accident in 2011 ... and you had to rehab for months to get back to normal ... would you risk it all for a killer physique??

Answer: ABSOLUTELY ... if you're Jason Derulo.

The "Whatcha Say" singer hit up a park in Sydney, Australia this weekend ... and bent over backwards for some kind of a handstand, pushup thing during a topless workout.

As we previously reported, J.D. screwed himself up bad just 2 years ago ... breaking his neck while doing tumbling and acrobatics during rehearsals for his tour.

Clearly, the guy feels confident his body is fully healed.

You're looking at the 2nd best ass in Brazil. Yes, the SECOND best -- and it belongs to Andressa Urach ... who hit the beach in Portugal, and decided to do a little topless sunbathing.

Andressa was 1st runner-up in the 2012 Miss Butt Brazil pageant -- or Miss Bumbum as the locals call it -- a nationwide contest to find the country's blue ribbon rear.

Click through the gallery ... Andressa's boobs must be sick of taking a backseat to her ass ... 'cause they came out to play.

BUN FACT: The best ass in Brazil, according to the MBB 2012 judges, belonged to Carine Felizardo. Now you know.

It was only 71 degrees on Staten Island yesterday, but Ashley Greene made it seem a whole lot hotter ... flashing some side boob in a teeny yellow bikini during a movie shoot in NY.

A pink and white beach blanket just barely managed to conceal the goods ... as Ashley filmed a scene for "Staten Island Summer" at the Great Kills Swim Club ... where some of the locals were used as extras.

The movie's about a couple of dudes who take jobs as lifeguards while trying to figure out what to do with their lives.

Why would you ever do anything else?