It’s about to be a-WHAT-Girl Fight! All hell is about to break loose now that Paris Hilton has learned her ex-BF, Greek shipping heir Stavros Niarchos, has reunited with former flame Mary-Kate Olsen. MK was left heartbroken when Stavros sacked her after a five month romance for greener pastures (filled with unlimited cumshots and blow jobs) with the Hilton heiress. But back Starvos has crawled on his hands and knees telling Mary-Kate that he is ‘a changed man’ and wants her back.

“Mary-Kate has wanted him back for a while now,” a snitching snoop tells In Touch Weekly.

Rumors of a reunion first sprang up on Oct. 24th. Mary-Kate and Stavros were caught getting cozy at an affair at L.A’s Paramour Mansion:

“They had some wine and champagne, and when the cameras were gone they started kissing.”

The reunited pair were again spied snuggling up to one another at Hyde Lounge on November 12th.

“They sat together and talked for most of the night.”

“They were super into each other,” Hyde clubgoer Susan McGinley spilled to Life & Style.

Which brings us to the pissy heiress. Upon hearing of the public makeout fest at Hyde, Paris hit the roof:

“She thinks MK was publicly hooking up with Stavros just to piss her off,” a Hilton source tells L&S.

“Mary-Kate has hated Paris ever since. Paris believes Mary-Kate is just trying to get back at her. Paris is totally over Stavros. She thinks he’s too young for her,” the Paris insider says matter-of-factly.

Star Magazine reports:

“They spend hours on the phone and even had dinner recently. They discussed what went wrong before. They have a lot of regrets and say they should have done things differently.”

“Mary-Kate truly loved Stavros, and hanging out with him again proved that she hadn’t completely gotten over all those feelings.”

Star claims Mary-Kate is not only dating Stavros again, but she’s also seeing NY Rangers hockey player Steve Avery.

“She doesn’t understand why Paris is always picking on her. She just wants to get on with her life.”