Hook Ups

And now, definitive proof Arnold Schwarzenegger and Maria Shriver are definitely maybe BACK TOGETHER -- Arnold totally grabbed Maria's butt last weekend ... and TMZ has video.

As we reported, Arnold and Maria were attending their daughter Christina's graduation at Georgetown ... and while people were milling around everywhere, Arnold casually cupped Maria's backside. It's subtle, but it happened.

FYI, Arnold has been obsessed with Maria's caboose since he met her in the '70s -- in fact, Arnold recently told a story on "60 Minutes" about how he told Maria's mother her daughter had a "great ass."

One day after Lindsey Vonn was spotted playing mom by dropping off his kids with Elin Nordegren at school alone, Tiger Woods joined in on the child-rearing fun.

Looking like one big happy family, Tiger and Lindsey -- who have been dating for around 5 to 6 months -- made the early morning trek to drop off his adorable children at their Palm Beach school on Tuesday.

Good news for fans of hot girls making out with each other -- Rihanna says she's totally down to suck face with Miley Cyrus ... just as soon as Miley calls her up.

So, WHY is Rihanna talking about girl-on-girl action with Miley, you ask??

Long story short -- someone asked Miley the same question (in reverse) recently and M.C. said she'd "definitely" makeout with RiRi.

So, we found Rihanna this weekend on her way out of Giorgio Baldi and asked if the hypothetical feelings were mutual.

... and they are!

In what appears to be their first public out since they split last month, Sharon and Ozzy Osbourne had lunch together today in Beverly Hills ... TMZ has learned.

According to our sources, the two dined at the Polo Lounge at the Beverly Hills Hotel. We're told Ozzy arrived first, accompanied by another man, and Sharon arrived a short time later.

The three dined at a booth inside, with our sources saying Sharon and Ozzy did not appear "romantic" ... rather more like a business lunch ... but the two were definitely talking.

As TMZ first reported, Sharon has been telling friends she would not consider getting back together with Ozzy until he proves he's sober for good this time. Last month, Ozzy wrote on Facebook that he had been sober since early March ... so if he has stayed clean, he'd be about 2.5 months sober now.

Time will tell if that's proof enough for Sharon that Ozzy has changed his ways.

It's official ... Justin Bieber and Selena Gomez are officially a pair once again!!!!!!!!! At least in their seats at the Billboard Music Awards this weekend.

Photos of the seating arrangements have surfaced on the Internet -- and you can plainly see, Justin and Selena will be seated next to each other at the award show on Sunday.

And for anyone thinking it's an accident -- celebs can easily request to sit apart from people if they really want to ... so it's obvious, neither Justin nor Selena had a problem being so close to one another.

Justin and Selena split last year, but ever since then they've been on-and-off-again more than Lindsay Lohan's movie career -- so this could finally be a sign they're back together.

Breathe easy, James Deen ... Farrah Abraham is NOT PREGNANT ... not even a little bit, as far as she knows.

The "Teen Mom"-slash-porn-star pre-taped an episode of upcoming conflict resolution talk show "The Test," where producers convinced her to take one -- and it was NEGATIVE. (Trust us, that's a POSITIVE).

TMZ broke the story ... Abraham said she missed her period after making her porno with Deen. She was photographed while plunking down cash for an EPT at the drug store.

But Farrah told "The Test" host Kirk Fox that she never took that test (her explanation was WAY too convoluted to make any sense ... so we're going with "not enough cameras around").

We're told Farrah reacted indifferently. We can relate.

Rocky's boxing gloves ... Dorothy's ruby slippers ... Indiana Jones' bullwhip ... the bikini Farrah Abraham wore on the cover of her sex tape -- one of these pieces of cinema history CAN BE YOURS!!! --- take a guess which.

Vivid Entertainment -- the porn studio behind the release of "Farrah Superstar: Backdoor Teen Mom" -- listed Farrah's pink crystal-encrusted two-piece on eBay at midnight ... and bids started at $500.

It's pretty hilarious ... the listing advertises the Poolside Collection bikini as "used" -- we're told that means exactly what you think it means: the bikini wasn't washed since Farrah wore it. Think Monica Lewinsky and The Gap.

In fact, we're told the bikini shows overt signs of wear, including fake tan stains and glitter from Farrah's body lotion.

As the listing goes ... "Farrah's bikini ... straight off Farrah's body and into your hands."

As if your hands won't already be busy enough.

Tiger Woods lost the shirt off his back ... and this time his ex-wife Elin Nordegren had nothing to do with it.

The 37-year-old golf star aired out his man nipples and soaked up the sun by going shirtless on his yacht in Palm Beach on Tuesday.

While his fancy schmancy boat is called Solitude, Tiger spent the afternoon lounging and fishing with his two adorable kids and his sexy bikini-clad girlfriend Lindsey Vonn yesterday.

Newly minted porn star Farrah Abraham is so worried James Deen knocked her up while filming their infamous sex tape ... she peed on a stick.

Sources close to Farrah tell TMZ ... the former "Teen Mom" star hadn't had sex in more than a year before James got her ... and the duo didn't wear condoms while filming ... and Farrah wasn't on birth control. Basically all the makings for an after school special.

We're told Farrah recently missed her period and started freaking out, thinking she was growing a little porn spawn. So she went shopping for a pregnancy test at her local pharmacy.

We're going to go to out on a limb that she's NOT pregnant ... for 2 reasons.

1. We've seen the tape, and you don't get pregnant THAT way.

Tiger Woods and Lindsey Vonn made their relationship red carpet official ... by holding hands at the Costume Institute Gala in NYC on Monday.

This is the sports super couple's first public display of affection since revealing they were bangin' by posting cheesy pics together on Facebook back in March.

In a glimpse of what may lie in their near future, Lindsey wore a virginal white gown as they walked down an aisle together.

Ironically, Tiger's next gig is competing in The Players Championship ... something he knows all about.

Farrah Abraham clearly has STDs on the brain ... 'cause that's all she wanted to talk about last night.

The "Teen Mom" star was outside Katsuya in Hollywood ... when we asked about her new 6-figure endorsement deal for a weight loss product.

The fun part -- we asked if she was present for lab testing (on the product) ... but Farrah thought we were talkin' about her vagina. She was very forthcoming, as usual.

Please don't squeeze the Neil Patrick Harris.

During a Race to Erase MS charity gala in L.A. this weekend, Elton John's husband David Furnish gave the "Doogie Howser" star a real helping hand ... by copping a sneaky feel of his butt.

As Sir Elton, Neil Patrick and his partner David Burtka posed for pics in a friendly embrace, Furnish tried to get away with pulling the old underhanded ass grab on NPH.

The truth always comes out in the end.

Antoine Dodson tells TMZ ... he's no stranger to the ways of the vagina ... claiming he had real-life sex with women before he switched to guys ... and says, "It was fun."

Dodson -- aka the "Bedroom Intruder" guy from YouTube -- said he's "no longer into homosexuality" ... and vows to live a straight life that falls in line with his new Hebrew Israelite religion.

We shot Dodson a few questions about his decision, here are his responses:

TMZ: "Do you believe homosexuality is a choice?"
Dodson: "I feel like homosexuality is put on people at early ages the things we see and hear and what's exposed to us."

TMZ: "How do you feel about sex with women?"
Dodson: "Sex with women is not new to me. It was fun. I did get enjoyment out of it. I was hurt by a woman as a teen."

TMZ: "Do you think homosexuality can be 'cured?'"
Dodson: "I believe when you get to a certain age, you feel different about things and things change, you begin to want more."

Dodson called into TMZ Live today...

Right before Jason Aldean filed for divorce ... the country star called the "American Idol" hottie he kissed behind his wife's back and warned her about the media firestorm to come ... TMZ has learned.

Sources connected to Brittany Kerr tell us ... Aldean placed the courtesy phone call himself last week ... and politely warned the singer that he was pulling the trigger on his marriage to his high school sweetheart Jessica Ussery.

Translation -- the media's gonna be all over your ass again ... so, govern yourself accordingly.

We're told Kerr appreciated the heads-up ... considering she was Aldean's kissing partner on the night he cheated on his wife back in Sept.

Since the warning, Brittany's been laying low -- shutting down her social media pages and staying out of the public eye.

It's not clear whether Aldean and Kerr have communicated since … or whether their relationship has a future.

There are a lot of things Louisville Cardinals guard Kevin Ware can't do since suffering one of the more gruesome injuries in sports history ... but he told our photog yesterday in DC ... he can still get down with the ladies.

And really ... that's all that matters, right?