Kris Humphries and his on-again girlfriend Myla Sinanaj are so chummy ... the NBA star actually gave Myla his ridiculously expensive Mercedes-Benz -- at least for now.

Myla arrived home to her house today in Rutherford, NJ driving Kris' white Mercedes -- and we KNOW it's his Mercedes because he's been driving the same car forever ... long before Myla even entered the picture.

We asked Myla what she was doing in the whip, and she insisted, "It's my car. It's not his car."

Which means she's either bending the truth, or Kris actually gave her the ride. In either case, it's obvious things are heating up between the two.

Nevertheless, Myla says, "We're just friends, hanging out."

Suuuuuuuuuuuuure.

Kris Humphries' closest friends and family were BLINDSIDED by TMZ's footage of the NBA player hanging out with his ex-girlfriend -- telling us, they now believe Kris is in a full-blown relationship with Myla Sinanaj ... and has been lying about it for months.

If you recall, Kris had sicked the FBI on Myla in the past ... telling the feds she tried to extort him by demanding a large sum of money, or else she'd release damaging information about their relationship to the media.

Kris told friends he was totally done with Myla ... insisting she was nothing more than a one night stand. Now his friends and family know ... he was lying through his pearly white teeth.

Sources connected to Kris' inner-circle tells us ... they had long-suspected he was secretly getting back together with Myla, but the video of the two leaving her home in Jersey together this week is the smoking gun they were waiting for.


When his inner circle confronted Kris about the TMZ footage, we're told Kris refused to answer any questions ... and changed the subject.

As for Kris' extortion allegations, Myla denied the claim ... and her lawyer even drafted a 26-page defamation lawsuit against the NBA star.

Seems like they've kissed and made up.

Kris Humphries has been adamant ... he never dated Myla Sinanaj. Myla swore during her deposition in the Kim Kardashian divorce case ... she and Kris were just friends. Well guess which friends apparently spent the night together this week?

TMZ shot video of Kris and Myla leaving her house in Rutherford, New Jersey Tuesday. He was inside the house for several hours. And we're told ... Kris' car was parked outside the entire night Monday.

Remember ... during Myla's depo ... she testified she was never pregnant with Kris' baby (even though she told various people she was), and Kris never spoke a word to her about his divorce.

The question -- have Kris and Myla been hooking up all along, and did she tell the truth during her depo?

So we gotta ask ...

Kris Humphries' ex-girlfriend says Kris was just a friend whom she never even texted ... and she denies Kris paid her off to keep her quiet ... TMZ has learned.

Informed sources tell TMZ ... Myla Sinanaj -- who was deposed by Kim Kardashian's lawyer today in New York City -- testified she didn't date Kris, she was never pregnant and she never got any money from him.  As for whether she had sex with Kris, Myla's lawyer instructed her not to answer the question.

Myla also said she never considered filing a lawsuit against Kris for telling the FBI she tried to extort him.  Tell that one to Myla's former lawyer, Joe Tacopina, who drafted a 26-page defamation lawsuit on her behalf.

Myla insisted she was not paid off.  By the way, we're told she no longer works at the New York hotel where she had been employed.

Myla Sinanaj -- who will sit for a deposition in New York City today in the Kris Humphries/Kim Kardashian divorce -- says Kim is a "cruel bitch" by scheduling her depo on the 1 year anniversary of Kris and Kim's wedding.

TMZ has learned ... Myla is telling friends she will testify that Kris repeatedly told her Kim defrauded him in the marriage, grousing that he "got played."

Kris is fighting the divorce, insisting on an annulment based on fraud.  Kris claims Kim never loved him and married him only to spike ratings on her reality show.

Myla says Kris -- who made hundreds of thousands of dollars off "Keeping Up with the Kardashians" as well as the wedding special -- "hated the cameras and his life being on display."

Myla is telling friends her relationship with Kris is "dead," so she has nothing to lose by telling the truth, and therefore she will be "100% honest" in answering questions during the depo.

The wild card -- Myla is not saying how she will answer questions about allegedly getting knocked up by Kris.  She previously told various people he got her pregnant ... then recanted the story.

Kim Kardashian just got a WARNING from a woman with whom she has something in common -- Kris Humphries ... and the warning is ... BACK OFF!

Myla Sinanaj just tweeted to Kim, "Why don't u enjoy ur Miami trip and stop sending private investigators to my house-Stop dragging me into ur drama."

Myla followed that up with, "I don't have to explain Or apologize for who I chose to be friends with.  Subpoena or not!"

Myla is referring to a subpoena from Kim's camp ordering her to sit for a deposition at the end of the month.  The depo involves Kim's divorce from Kris -- something Myla may know a  thing or 2 about.  Myla's ex-lawyer, Joe Tacopina, already accepted service on Myla's behalf, but it seems Kim's camp may be worried Myla may now say he didn't have authority to do that.

Myla also just tweeted, "Subpoena me twice for the same thing!  Hilarious."

Well, Myla, you can never be too careful ... and that doesn't just apply to getting pregnant.

Now that his ex-girlfriend Myla Sinanaj says she's 100% not pregnant with his spawn, Kris Humphries celebrated by partying shirtless in South Beach this weekend.

With no more baby mama to worry about, the 27-year-old flashed his Calvins while throwing back cocktails with pals.

Miami is brutally hot in the summer, hopefully Kris used protection this time.

Kris Humphries can breathe a sigh of relief -- his ex-girlfriend Myla Sinanaj insists she's NOT PREGNANT ... her belly's just naturally round.

Myla was out in Jersey earlier today, where a photog asked her straight -- are you pregnant or not? Myla responded, "I am definitely not pregnant."

What Myla DOESN'T explain is why she texted her lawyer Friday night that she WAS pregnant -- and why she told numerous other people, including Kris, that she was expecting.

Myla's latest version is that people just started talking and, "Of course, me not being a size zero kept it going."

That, and her lying about being pregnant.

Kris Humphries believes he's the next Kim Kardashian -- as in, dude believes he wields the power to make someone famous with the snap of his finger ... and last night, he tried to prove it.

Humphries was leaving AV nightclub in Hollywood around 2 AM ... when we asked him about the baby mama drama in his life. But Kris wasn't in the mood to discuss parenthood ... instead, he promised to "blow up" our photog (in a good way) by taking his pic and posting it to Twitter.

Kris -- who was very nice BTW -- took our guy's pic and was ready to tweet at him ... but there was one really big problem ... you can't tweet at a guy who doesn't have a Twitter. Bummer.

As for Kris' whole "Is my ex-gf pregnant?" thing ... just doesn't seem like he cares.

Kris Humphries' ex-girlfriend Myla Sinanaj just tweeted this photo, writing, "Loook No Babyy bump!" ... which raises several important questions:

-- Is she pregnant, or isn't she?
-- Did she have an abortion?
-- Was she ever pregnant?
-- Did Kris ask her to tweet (She wants back with him)?
-- Why did she tell her lawyer, Joe Tacopina, she's pregnant?

Myla added, "Yes I'm a thick curvy girl ... All natural I'm comfortable in my skin."

So many questions ... so let's start with #1 ...

It's no accident Myla Sinanaj says she's pregnant with Kris Humphries' baby -- sources close to Myla tell TMZ ... the two had unprotected sex all the time. 

According to sources close to both Kris and Myla, Humphries was nonchalant when it came to using condoms. We're told if there wasn't one handy ... Kris had no problem going about his business.

As TMZ first reported, Kris isn't 100% sure he's the baby daddy, but Myla maintains she hasn't been with anyone else since she started seeing Kris.

And BTW ... sources close to Kim Kardashian tell TMZ she's laughing over the whole thing. We're told she finds it funny that Kris wants an annulment because he's a good Christian boy, yet he knocked up some other girl while he's still married.

How do you say "schadenfreude" in Armenian?