
A fire truck rushed to the home of
Katherine Heigl moments ago -- but TMZ has learned ... it was a steamy false alarm.
A rep for L.A. City Fire tells TMZ, a call was placed at 1:36pm reporting a possible fire -- and firefighters scrambled to the scene.
But Katherine's rep tells TMZ, the alarm was triggered by some steam inside the house -- the source is unclear. No one was hurt.
It's also unclear if Katherine was home at the time -- but her husband
Josh Kelley (above) greeted firefighters at the gate ... before sending them on their way.
Katherine Heigl's mom had some serious shaking going on during a day of beauty -- and the cause of her faux seizure may or may not be Katherine's new movie.

Somehow
Lea Michele,
Katherine Heigl and
Sofia Vergara all agreed to star in that "
New Year's Eve" movie.
Question is ...
Katherine Heigl has officially gone into business with her mother, each investing close to a MILLION bucks so they can be co-owners of a bunch of luxury condo units in L.A.. ... TMZ has learned.

According to documents filed with the L.A. County Recorder's Officer, Heigl and Mama Heigl have each shelled out $850k towards an investment group which bought 8 condo units in Sherman Oaks, Ca.
The units ain't too shabby -- with hardwood flooring, granite counters, balconies and fireplaces.
Plus, the condo building is right down the street from an In 'n Out Burger!! Location! Location! Location!
The only thing hotter than
Katherine Heigl in a black bikini ... her electronic cigarette.

The 32-year-old former TV actress soaked her bones in the Miami sun this weekend.
Addicting.
We took your questions today on everything -- including
Lamar Odom being managed by
Kris Jenner,
Paris Hilton's trespasser being arrested,
and
Katherine Heigl's neighborhood war.

Plus:
Courteney Cox and
David Arquette's trial separation.
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Cops were called to the home of
Katherine Heigl last night after a little neighborhood war erupted over noise in a hot tub ... law enforcement sources tell TMZ.

We're told Katherine and hubby
Josh Kelley were enjoying time in their hot tub Monday night when a neighbor started screaming obscenities at them from over the fence, complaining of noise. The couple's security guy called the cops, who came to investigate just after 10 PM.
Cops came inside the Los Angeles home and spoke with the couple, who told officers the neighbor had noise issues with many other property owners as well.
We're told cops determined no crime was committed and they left.
"
Gossip Girl"
Blake Lively and former "
Grey's Anatomy" star
Katherine Heigl both roamed the streets of NYC on Tuesday.

Question is ...
Ashton Kutcher's wife
Demi Moore, 47, and his "
Killers" co-star
Katherine Heigl, 31, canoodled at the same event in Hollywood on Tuesday.

Question is ...
Last night in Hollywood,
Katherine Heigl was stuck in a situation worse than a "
Grey's Anatomy" subplot involving sex with a ghost: Traffic and a whole lotta paps.
While out with her husband and parents in L.A. yesterday, Katherine Heigl chowed down on a huge lunch of wine and smokes.

How does she keep that girlish figure?!