12:18 PM PT -- TMZ spoke with a rep for the Evanston Police Department ... who tells us Kristin was initially stopped for speeding early this morning.
During the stop, the officer learned Kristin has been living in the state and driving without a valid IL license, which is against the law in IL.
Cops say Kristin was required to travel to the police station, in her own car, and was ultimately hit with a citation for $120 ... despite the fact that EVERYONE ON THE PLANET knows she splits her time between L.A. and Chicago because she's married to Bears QB Jay Cutler.
Cops say if Kristin wishes to continue driving in the state, she must get a valid IL driver's license.
Kristin Cavallari says she was taken into police custody in Illinois this morning -- and forced to post bail -- and claims it all has to do with her driver's license.
KC went to Twitter moments ago and said, "Who knew having a California driver's license in Illinois was a CRIME to be escorted to the police station to post bail?!! What a morning."
The former MTV star -- who's married to Chicago Bears QB Jay Cutler -- is insinuating that she had the same problem Justin Bieber had in L.A. ... when he was cited for not having a valid driver's license.
In Illinois, you are required to have an IL driver's license once you have lived in the state for 90 days ... or you can be cited.
However, KC says she's not a full-time IL resident and therefore shouldn't be subjected to that law. She also tweeted about it saying, "I still have an apartment in LA so I'm a resident of California."
Story developing ...
Heidi & Spencer
Still Alive ...
Celebrate Bday In Vegas
9/1/2013 12:43 AM PDT BY TMZ STAFF
What did Spencer Pratt do for his 30th birthday? He watched his plastic girlfriend Heidi Montag jump out of a plastic cake at a strip club in Vegas. Woooo adulthood.
Spencer, looking a little fuller these days, celebrated the day of his birth inside the VIP section of famous strip club gentleman's club Crazy Horse III on Saturday along with Heidi and friends.
In the pics Heidi goes all Marilyn Monroe on a giant fake cake. Spencer looks pretty happy about it.
Probably because her boobs are giant. And now you know.
GIVE ME 5 DOLLARS
8/22/2013 6:11 AM PDT BY TMZ STAFF
This video is pretty great ... Kristin Cavallari messing with the paps after a night of clubbing in Hollywood -- shakin' 'em down for cab fare in exchange for a photo ... and it's awesome.
It's that classic KC bitchiness we all know and love ... with the reality star shaming the paparazzi for $5 outside Hooray Henry's in Hollywood -- "I just posed for you. Pony the f*ck up."
Eventually, one of the snappers opens his wallet ... but Kristin was clearly not impressed.
It's not like she needs the money -- her husband Jay Cutler is at the end of a 5-year $50 million contract.
Still, gotta take what you can get.
Cutler & Cavallari
If At First You Don't Succeed ...
6/12/2013 4:30 PM PDT BY TMZ STAFF
Jay Cutler & Kristin Cavallari
We're Finally Getting Married
... In Tennessee!
6/7/2013 10:52 AM PDT BY TMZ STAFF
Jay Cutler is finally gonna make an honest woman out of his baby mama ... TMZ has learned the Chicago Bears QB just purchased a marriage license in the state of Tennessee.
We've confirmed ... Cutler and Kristin Cavallari appeared at the Davidson County Clerk in Nashville, TN early this morning ... and dropped $99.50 on the paperwork required to tie the knot.
Sources connected to the couple tell us ... the two are set to swap "I dos" at a ceremony THIS WEEKEND in Nashville ... the city where Jay went to college (he played at Vanderbilt).
The marriage license is only valid for 30 days ... so if Jay has a last minute change of heart this weekend, Kristin still has a couple of weeks to change his mind.
Jay and Kristin were originally engaged back in April 2011 ... but called it off in July.
Just a few months later, they announced the engagement was back on ... and in January 2012, they revealed Kristin was preggo with Jay's kid.
Kristin gave birth to their son Camden on August 8, 2012.
So far, no comment from Cutler or Cavallari.
UPDATE 12:33 PM PT -- Kristin posted a pic to her Instagram of a pair of wedding rings with the caption: "Im officially Kristin Elizabeth Cutler!!!!!"
Still Got 'Hills' Money
Buys $3.7 Mil L.A. Home
4/18/2013 4:30 PM PDT BY TMZ STAFF
Lauren Conrad might be old as the "Hills" ... but she's still rich as ever ... plunking down $3.74 million on her new L.A. mansion.
Sources close to the deal tell TMZ, the 27-year-old former MTV star purchased the 4,300 sq. ft. 6-bedroom, 5-bathroom Brentwood home this week.
It's two stories ... with a brand, spanking new kitchen, huge backyard and a basketball court. It was remodeled recently by celeb interior designer Jeff Lewis from Bravo's "Flipping Out."
Not a bad purchase ... especially for someone who used to be best friends with Heidi Montag.
Winter Bikini Beach Day
2/6/2013 10:30 AM PST BY Johnny Lopez
I'll Go Home with You
In a Bikini ... for 12 Months
12/29/2012 6:20 AM PST BY TMZ STAFF
Former "Hills" star Audrina Patridge is selling her bikini-clad body (again) -- stripping down for a smoking hot 2013 swimsuit calendar -- and TMZ has every month's picture.
Trust us, it's awesome. In fact, it has everything you could ever hope for ...
Audrina's boobs ... check.
Audrina's boobs oiled up ... check.
Audrina's boobs by a pool ... check.
Audrina's boobs on a chair ... check.
Audrina squeezing a dog in her boobs ... check.
I'm Still Relevant, Dammit!
11/8/2012 9:55 AM PST BY Johnny Lopez
Former reality trainwreck Heidi Montag took a break from living in obscurity to wash up on the beach with all her augmented fake body parts in a skimpy red bikini in Santa Monica on Wednesday.
The 26-year-old former "The Hills" star -- who infamously had 10 plastic surgery procedures in one single day back in 2009 -- did some of her best acting while hamming it up for the cameras on the sand.
Who needs a lifeguard when you have built-in triple D floatation devices at all times?
Audrina Patridge in a Bikini
Ho-hum ... More Bikini Photos
5/13/2012 8:55 AM PDT BY TMZ STAFF
Audrina Patridge in a Bikini
The Hills Are Back
5/11/2012 11:15 AM PDT BY Johnny Lopez
Former "The Hills" actress Audrina Patridge took time off from her busy schedule of wearing a bikini in L.A. ... to show off her slammin' body in a white hot bikini at the ME Cabo Hotel in Mexico yesterday.
Audrina is down in Cabo San Lucas celebrating her 27th birthday with her BMX boyfriend Corey Bohan and some family members.
All of Audrina has grown up quite nicely.
Beverly Hills ...
That's Where I Want to Be
4/14/2012 4:00 AM PDT BY TMZ STAFF
Former MTV star Lauren Conrad is back on "The Hills" -- Beverly Hills -- because she just dropped $1.35 million on a swanky new condo in the wealthy L.A. neighborhood.
The ex-reality star will be the newest resident of the 90210 -- recently purchasing the massive 3,200 sq. ft. 2-story, penthouse condo with 3 bedrooms, 4 baths, and a 24-hr security system ... to keep away all those crazy "Hills" fans.
The house also sports a rooftop pool, outdoor deck, full gym, indoor bar, marble bath and hardwood floors.
But all this doesn't come cheap -- Conrad has to shell out $2,319 in homeowners' fees alone ... and then pay her million dollar mortgage on top of that. Oh, and this is her 2nd house -- the other one is in Malibu.
All hail LC.
Family Loses 'Laguna Beach' Mansion
3/30/2012 4:00 AM PDT BY TMZ STAFF
Kristin Cavallari has some problems back on the home front ... because her family has officially lost their ocean-front mansion featured on "Laguna Beach" after falling behind on mortgage payments.
The house is INSANE -- 5 bedrooms, 5 baths, ridiculous infinity pool, dry sauna, wine cellar, yoga room and some of the sickest beach views you've ever seen in your life.
But TMZ has learned ... the bank recently foreclosed on the property because, according to official documents, KC's father Dennis failed to make payments on the $7,599,458.66 he owed on the place.
And now it's too late for the Cavallari's to get the place back ... because the house was sold at a public auction just last month for $6.1 mil.
Calls to Kristin's rep have not been returned.