The 21-year-old actor was spotted “making out” with newly-single heiress Paris Hilton at a party for his new show on Monday night. According to an on-looker Paris just couldn’t contain herself around Paul:

“Paul was hanging with his friends and all of sudden someone was behind him and his friends started pointing [...] It was Paris. She grabbed him and just started making out with him.

On the show, Paul plays a geeky teen who has a very large, uh, package. Maybe Paris was hoping that the TV show’s premise was based on reality?

Paris and Paul both tweeted photos of themselves snuggling up together at the party, leading us to believe that maybe they were just kissing as part of a friendly joke. After all, Paris has close ties to the show: sister Nicky Hilton is dating the show’s creator, David Katzenberg.

Despite the fact that Flickinger, 24, recently tagged along with the sisters and Nicky’s beau David Katzenberg, 25, on a holiday trip to Australia—or perhaps because of it—Page Six reports that Paris’ sibling laid down the law regarding Brittany at the Sundance Film Festival.

The site claims Nicky, 25, forbade Paris, 27, and Brittany from staying at Jeffrey Katzenberg‘s house in Utah. Therefore, her sister ended up in a condo with Aubrey O’Day.

The heiress and the former Danity Kane singer reportedly struck up a fast friendship, and left Flickinger out in the cold.

“Paris kept ditching Brittany for Aubrey,” says a Page Six source.

After being left by Paris at the Eldridge, so-called BFF Flickinger found Hilton and O’Day at 2:00 a.m. across the street at Tao.

“She was crying and screaming, ‘Paris, stop leaving me!’,” the source added.

Geez, with best-friends-forever like that…

No photos yet of Paris and Brittany kissing and making up—though Aubrey might encourage them to do so.

Paris Hilton‘s lil’ sis, 25, was spotted crossing the street in Hollywood, dressed in short-shorts and some skyhigh heels.

She looks slightly healthier than she’s looked in the past. Perhaps her recent payday encouraged her to get to Ralph’s.

The heiress, who has been dating movie mogul Jeffrey Katzenberg‘s son David, 25, for two years (is that who she’s speaking with?), isn’t one to rest on her trust fund.

Besides producing several fashion lines over the years, she’s also a sought-after party guest.

Nicky and sister Paris Hilton recently earned a sum that was rumored to be between $600,000 and $750,000 (each) for partying the night away in Sydney, Australia, at the Bongo Virus New Year’s Eve Party.

And last NYE, in Las Vegas, was no different. Paid to party!

If Paris, 27, looks at all sad, it’s only because she couldn’t drive her new pink Bentley to Australia.

Clad in a turquoise sweatsuit with matching shades, the recent crime victim seemed animated and welcoming as she waved to photographers and signed a few autographs.

Little sis Nicky, 25, looked slightly more dour in black and gray.  Nicky might actually have been asleep behind her own sunglasses. Jet lag from such a long flight can take its toll.

The girls were accompanied by Paris’ new reality show BFF Britanny Flickinger, 24, and Nicky’s boyfriend David Katzenberg, 25.

News.au.com reports that Paris’ media frenzy continued after she and the Socialite Scooby Gang (and their 16 bags of luggage) checked into South Yarra’s Como hotel.

Hilton shopped on Melbourne’s Chapel St. and then had dinner with the gang at Stokehouse in St. Kilda.

The Hiltons and entourage will only be staying in Melbourne until Tuesday night, at which time they are off to Sydney to host the Bongo Virus New Year’s Eve party. So get your rest now, Australia. The Hilton sisters will allow for party slackers!

• Hugh Jackman, at the Los Angeles unveiling his upcoming epic Australia costarring Nicole Kidman, then the Jacob’s Creek’s after party with director Baz Luhrman and fellow Aussie Rachel Griffiths.
• Sweethearts Nicky Hilton and David Katzenberg, chowing down on Korean barbeque at Hollywood eatery Shin.
• Brittany Murphy touching up her blonde locks at Beverly Hills’ star haunt Neil George Salon.
• Katie Couric, nabbing the highest bid at a charity auction ($19,000) for a private tour of CBS with the anchor herself, at p.i.n.k. vodka and Anthropolgie’s Raise Your Voice Girls Learn International Fall Benefit.
• Lucy Liu and stylista Rachel Zoe, celebrating up-and-comer Jason Wu‘s MySpace-hosted trunk show at Satine Boutique in West Hollywood.
• Brothers & Sisters Dave Annable, calming down a margarita-happy brunette at Jennifer Aniston-fave LA mexican spot Marix.
• Transformers hottie Megan Fox, rocking no makeup and glasses for a romantic dinner with fiance Brian Austin Green