Kim Kardashian is really becoming Paris Hilton day by day. Her latest similarity to the heirhead? Fighting with Shanna Moakler! In a fight we wish had been caught on cameras for reality TV, Shanna threw a drink at Kim and called her, er, "promiscuous" at a party last weekend, Page Six reports. And surprise, surprise -- it's all about Shanna's ex-hubby, Travis Barker.

Here's the back story: Kim once modeled for Travis' clothing line, Famous Stars and Straps. But according to Shanna, Kim wanted more than a working relationship with the +44 rocker. "She was sending him text messages and e-mails, and this was when Travis and I were working on [staying together]," Shanna says. "When it happened, I asked her, 'What are these e-mails?' She had no answers for me. She was blatantly disrespectful."

Fast-forward to last weekend, when both Shanna and Kim attended the same soiree. "I was going to leave, but I'm a human being. I get upset," she says. "I confronted her. She ruined my marriage and my family. If I get passionate about it, they call me crazy." (Uh, that tends to happen when you throw drinks, scream obscenities, and throw a fit at a party.) Shanna also made sure to relay the sordid tale to Kim's BF, Reggie Bush. So on Monday, Kim struck back by wearing a Famous Stars and Straps shirt in from of the paparazzi, an act that Shanna said was "in the poorest of taste." Kim actually agreed with her after the fact and apologized on her blog: "It was immature of me to wear [the shirt] out the other day. I just wasn't thinking." Still, Kim maintains that she "only had a professional relationship" with Travis.

OK, we get why she got angry, but is there anyone in Hollywood who Shanna hasn't had a catfight with? Who's next -- Abigail Breslin?!