An Australian billionaire hanging out with a bunch of scantily clad ladies in costume?! Sounds like a movie script! But leave it to world-famous playboy Leonardo DiCaprio to set up a night of debauchery between himself, 47-year-old media mogul James Packer, Brody Jenner's 22-year--old ex girlfriend Bryana Holly (who dressed as a slutty Grecian goddess), some nameless slutty Wonder Woman, and a few more slutty sluts.

Uhh we wonder what antics this group got up to?! We're sure these well-meaning rich dudes and these classy ladies just played a good round of wholesome checkers together or gathered some canned goods to bring to a food bank. Yeah ... right ...

After enjoying a Halloween-themed dinner at Nobu on Saturday, Leonardo, Steve, Brody Jenner's and the other women climbed into DiCaprio and Packer's car to continue their night of fun, making their way to Hollywood nightclub, Blue Collar.

We were a little surprised to see Packer hobnobbing with an A-lister like Leo, but it turns out that Packer has just formed his own production company, RatPac Entertainment, with super producer Brett Ratner.

Umm last we heard Packer, who is the third richest person in Australia and worth an estimated $7.9 billion, was dating Orlando Bloom's ex, Miranda Kerr. If they are still together -- we can't imagine the supermodel would be down with this sexy party. However, Miranda's been off spending alone with millionaire Steve Bing, who is Elisabeth Hurley's baby daddy. Over the weekend, we caught Miranda and Steve hanging out at his home in Malibu.

Those exclusive photos and more coming tomorrow …