The Kardashians

File this under: Things you NEVER say to your fiancee.

Kris Humphries was lumbering around L.A. yesterday when he was asked -- IN FRONT OF Kim Kardashian -- if he was with "the most beautiful girl in world" ... and HE SAID, gasp, NO!

TMZ has obtained a copy of Kim Kardashian's wedding invitation, and it has all the makings of a fancy schmancy affair.

The wedding, which will be held on Saturday, August 20, is strictly black tie.

The ceremony will be held in Montecito, California -- near Oprah's mansion.

Of course, the bash is being thrown by Kris Jenner and her sidekick, Bruce.

Another member of the Kardashian Klan has agreed to compete on the next season of "Dancing with the Stars" TMZ has learned ... but it ain't Khloe ... or Kourtney ... or Kris -- it's a dude!

Multiple sources confirm ... Rob Kardashian is officially on board -- despite concerns about the "Dancing" schedule conflicting with Kim's super MEGA wedding in August. We're told the two sides addressed the issue and hammered out a plan -- and Rob signed on the dotted line.

As TMZ first reported, Kim filed suit against Old Navy because she felt they were trying to intentionally deceive people into thinking she was a spokeswoman for the company by using a girl who looked just like her in their commercials.

But our sources say ... the suit was filed because Sears felt the Old Navy commercial compromised its ad campaign for the Kardashian Kollection -- an exclusive line of clothing and bedding that launches in about a month and a half.

We're told Sears execs actually questioned if Kim was part of the Old Navy ads. The company feels the ad creates confusion in the marketplace and that happens to be exactly what Kim needs to prove to win her suit.

Bottom line -- Kim doesn't care about KK wannabes ... but she cares a lot about a deal that could be worth hundreds of millions of dollars.

Khloe Kardashian originally debuted a picture of her hubby's new do on her Twitter last week -- showing stars shaved into his typically smooth head.

We're told Lamar had his barber, "G", give him the stars in honor of his cousin -- who used to call him "LaStar" while he played for the Clippers.

According to our sources, Lamar was being driven by a car service yesterday in Queens when the car struck a motorcyclist and a 15-year-old boy. Lamar was not injured -- but we're told he was particularly upset by the accident (and even crying afterward) since he was already in town for his cousin's funeral.

We were originally told Khloe was in the car with Lamar, but that was not the case. According to our sources, Khloe is in NYC with Lamar but was not with him at the time.

According to MediaTakeOut.com, which first reported the story, the motorcyclist and the 15-year-old boy were both seriously injured.

Sources close to the couple tell TMZ they've been going over their favorite passages in hopes of picking a few to be engraved on their wedding bands. We're told Kim will pick a passage for Kris' ring, and Kris will pick one to be engraved on Kim's.

According to our sources ... they are each taking it very seriously and they both want to pick something "with meaning."

As we previously reported, Kim already has a bible verse engraved into her massive engagement ring.

Sources close to Kim tell us ... Kardashian worked out a deal with Platinum Motorsports in L.A. ... which will provide enough vehicles to transport Kim's entire family AND Kris Humphries' entire family.

And get this -- Kim is color coordinating the cars to match the rest of the wedding ... and has specified that she only wants white vehicles. We're told Platinum Motorsports has told her it's not a problem.

Of course, the entire party won't be driving themselves -- we're told each car comes with its very own chauffeur.

To end all talk of butt implants or injections, little sis Khloe Kardashian posted a pic of Kim and her electromagnetic badonkadonk on her blog.

Sources close to Kim K tell TMZ ... her lawyers are drafting a defamation lawsuit against Lockett and will file it as early as Monday morning.

Kim has maintained all along she never met Bret -- despite his claims they had a "physical relationship." Harvey hammered Lockett on TMZ Live last week, asking him when and where he met Kim, but Lockett refused to say. Nevertheless, he insisted he and Kim had hooked up this year, after she started dating Kris Humphries.

But on Friday, Lockett finally fessed up on "Showbiz Tonight" ... admitting he never actually met Kim.

We're told Kim's lawyers fired off a letter to Lockett in the last few days, telling him to hang on to the so-called "evidence" he has on his "affair" with Kim -- because he'll need to produce it in court.

What a jerk.

You'll remember ... we tried pressing Bret during TMZ Live earlier this week for details on where he met Kim ... but he

A story is circulating ... London helped facilitate the alleged Lockett/Kardashian hook-up by scoring Bret's number at Kim request. But an attorney for London fired off a letter to In Touch Friday, claiming London has had an impersonator for a while now, and if the mag spoke to anyone claiming to be her ... they were barking up the wrong tree.

The letter goes on to state emphatically that London "has never spoken to anyone at IN TOUCH WEEKLY, does not know Mr. Lockett and did not introduce him to Ms. Kardashian."