The one-time BFFs are airing their dirty laundry on Twitter, and the latest accusation has Hilton (real name Mario Lavandeira Jr.) repeatedly issuing a statement about the whole thing on his blog.
This isn't the first time Hilton has gotten into it with a celebrity. His list of feuds includes spats with will.i.am., Khloe Kardashian and Miss USA runner-up Carrie Prejean.
But let's rewind on the current kerfuffle, shall we?
The exact origins of the Hilton-Gaga feud are unclear, but Hilton has repeatedly published tweets and blog posts with criticisms about Gaga's latest single, "Applause," calling it "meh" and pointing out its lackluster performance on the charts, especially when compared with Katy Perry's "Roar." Perry recently ousted Lady Gaga as the most followed female celebrity on Twitter too.
Gaga's fans, also known as Little Monsters, did not take the detracting lying down, unleashing a flurry of homophobic abuse at the openly gay blogger and his new son.
The "Born This Way" singer also posted a scathing tweet regarding a pic she'd reportedly received from Hilton following a hip injury at the beginning of the year that landed the singer in a wheelchair.
"Still have the text Perez sent me of me in a wheelchair w the words KARMA written across + Madonna pointing a gun at me. Day of my accident," she wrote on Aug. 16.
Again, the Little Monsters came out in droves and continued to threaten the gossip writer.
Hilton recently announced that he was relocating his family from Los Angeles to New York. Apparently he went house hunting in the Big Apple this weekend, when Gaga said fans tipped her off about him viewing an apartment in her building. That's when she lost it and lashed out on Twitter on Sunday.
"@perezhilton STAY AWAY FROM ME + MY FAMILY YOU ARE SICK TRYING TO RENT AN APARTMENT IN MY BUILDING TO STALK ME. LEAVE ME ALONE!!!" she wrote in tweets that have since been deleted.
"DO I NEED TO BE SHOT IT IN THE HEAD FOR PEOPLE TO UNDERSTAND THAT HIM AND EVERYONE ELSE THAT HARASSES ME HAS GONE TOO FAR? IM A HUMAN BEING"
Later that day, Hilton stood his ground, posting a statement titled "A Statement on Lady GaGa's Lies" under the "Personally Perez" section of his blog.
In the statement, he says that he lived in the Big Apple for six years in the mid-1990s and again last year for three months while he was doing an off-Broadway show.
"I'm a new father and I am primarily focused on my family and where we will be most happy," he said. "I love New York and that is where me and my growing family want to call home right now. Sunday, my realtor showed us a list of possible apartments to rent. I learned only after the fact that Lady GaGa lives in one of the buildings we looked at, and she was across the country in Los Angeles when I viewed that building.
"After a day of innocent house-hunting, I am devastated and my heart hurts that my former very good friend, a person I used to call my 'wifey' and traveled the world with, is making very public and very untrue allegations about me on Twitter. While it is still too painful for me to go into detail about why I chose to no longer make her a part of my life, I will say that I am a critic and not a 'stalker'. Any allegation that I am stalking her, based on a day of house hunting with my baby boy and my mother, is utterly false, defamatory and now appears to be putting me and my family in danger."