Jon Gosselin's ex-girlfriend wants to make one thing clear to the Octopop -- when push comes to shove ...
literally ... she will file a police report on his ass.

TMZ has learned
Hailey Glassman filed a harassment complaint against Jon on December 20 for allegedly pushing her against a wall inside his Manhattan apartment -- this according to the NYPD.
Jon's rep only gave one word in response: "FALSE."
As TMZ reported, Hailey Glassman moved her stuff out of Jon's pad last Wednesday.
The NYPD has already questioned
Jon Gosselin's ex girlfriend
Hailey Glassman about the vandalization and burglary of Jon's Manhattan apartment -- but law enforcement sources say no charges have been filed yet.

Sources tell TMZ Glassman -- accompanied by her attorney -- was questioned last night. As we first reported, the note that was left behind was signed with Glassman's name -- but that doesn't mean she has anything to do with the incident.
Our sources also say Jon is called a "cheater" in the note -- which was stuck to Jon's bedroom dresser with a knife -- but we're told there's no reference in the note to the destruction of Jon's apartment.
And there's this: Jon's lawyer said the NYPD fingerprinted the scene -- but Hailey used to live in the apartment with Jon, so her prints are gonna to be all over the place.
Jon Gosselin's ex-girlfriend is finally dumping all her relationship baggage -- into the back of a big ass moving truck.

Hailey Glassman was spotted carting her stuff out of the Octopop's Upper West Side apartment in New York City Wednesday morning ... for good -- the final nail in the break up coffin.
The couple reportedly split back in October.
Former Star Magazine reporter
Kate Major -- who insisted she was romantically involved with
Jon Gosselin -- is next in line to testify in TLC's breach of contract case against the famous reality dad.

TLC's lawyers have asked the court for permission to serve Kate with a subpoena, ordering her to testify along with other witnesses -- including
Michael Lohan and
Hailey Glassman -- in depositions scheduled for December 10.
Kate reportedly quit her job at Star Magazine to pursue a relationship with Jon. Last we checked, the Octopop denied ever having a relationship with her.
Jon Gosselin and his girlfriend
Hailey Glassman arrived to a dinner date at The Oak Room in New York in a horse and carriage.

That loud explosion you just heard would be Kate Gosselin's head exploding.
Jon Gosselin spent some of his hard-earned money to buy his girlfriend
Hailey Glassman some drinks at an Irish pub in NYC the other night.

No word if '
Entertainment Something' picked up a round too.
Jon Gosselin returned from France with two giant Gucci bags, $702 in cash and at least one douchey
Ed Hardy t-shirt. What he didn't come back with: His new GF, 22-year-old
Hailey Glassman.

Dude talked about almost everything -- where his new +1 went, his meetings with
Christian Audigier, the future of his show -- but wouldn't touch the subject when we asked what Kate thought of Hailey.
He "didn't want to get in trouble" with TLC ... but more likely feared an attack by Kate's wild porcupine reverse mullet.
His reality show may have ended his marriage, but it's also giving
Jon Gosselin a douchey clothing line for kids.

Jon -- with his new 22-year-old GF
Hailey Glassman by his side -- has been partying up in St. Tropez with bedazzler extraordinaire
Christian Audigier and are going into the children's fashion biz together -- with a line that might even be featured at Kmart. The best part, Jon's eight rugrats will be used as models for the clothing line.
Those poor kids need more fame about as much as they do a tacky, rhinestoned dragon and skeleton t-shirt.
Jon Gosselin and his new +1, Hailey Glassman, enjoy a smoke while aboard
Christian Audigier's yacht in Saint-Tropez.
Jon Gosselin was photographed earlier today in St. Tropez, holding hands with his girlfriend, Hailey Glassman.