Ashton Kutcher & Demi Moore

Demi Moore was rushed to the hospital Monday night ... and we're told the issue is substance abuse.

Law enforcement tells us a 911 call was placed at 10:45 PM Monday night. Paramedics responded to Demi's L.A. home and after assessing her for a half hour, she was transported to a local hospital.

Sources tell us she is being placed in a facility to "seek further professional assistance." Our sources say the treatment is for substance abuse.

Demi's rep tells TMZ, "Because of the stresses in her life right now, Demi has chosen to seek professional assistance to treat her exhaustion and improve her overall health. She looks forward to getting well and is grateful for the support of her family and friends."

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Ashton Kutcher's style wasn't cramped at all in the wake of Demi Moore's health crisis -- he was partying Tuesday in Sao Paulo, Brazil at a Bruno Mars concert and a nightclub.

Sara Leal -- the 22-year-old blonde who allegedly slept with Ashton Kutcher this summer -- insists she isn't responsible for the actor's crumbling marriage to Demi Moore ... telling TMZ, she was just a "bump in the road."

Less than two weeks before Demi Moore announced she would divorce Ashton Kutcher, he threw a Hail Mary to save the marriage ... in the form of a lavish, eco-friendly gift.

According to our sources, Ashton contacted a high-end car company, to buy a new set of wheels for Demi's birthday. We're told Ashton picked out a 2012 Lexus LS 600h L -- and paid North of $100,000.

Our sources say Ashton wanted a quick deal -- bagging the luxury hybrid on November 9, just two days before Demi's birthday.

If it was meant to win back Demi ... clearly it didn't work. We don't know if Demi accepted the vehicle or if Ashton was able to give it back to the car company.

Only in Hollywood can someone who slept with a married man claim they feel "lied to" -- but that's what Brittney Jones, Ashton Kutcher's alleged mistress, told our photog yesterday.

As TMZ first reported, Jones -- whose alleged tryst with Kutcher in 2010 was heavily denied by his camp -- says she felt vindicated when Demi Moore finally pulled the plug on her marriage to Ashton.

Jones said she hasn't spoken to Ashton lately but she wishes him and Demi the best.

Ashton Kutcher's alleged mistress -- the FIRST alleged mistress -- claims she feels "vindicated" by Demi Moore's divorce statement ... telling TMZ she hopes people will finally believe her story about sleeping with Ashton.

TMZ spoke with Brittney Jones -- who claimed she got busy with Kutcher in 2010 after meeting the guy at a bowling alley. Jones' credibility was called into question when she capitalized on her sudden fame by releasing a sex tape .... which did NOT feature Ashton.

Ashton's lawyer released a statement at the time Brittney was in the headlines, insinuating her story was a lie ... but not entirely denying

Now, Jones tells TMZ ... "Although divorce is often sad I do feel somewhat vindicated."

She adds, "For so long people have thought that I was dishonest or just making up my passionate nights with Ashton, when in fact I was being used."

"Ashton told me that both he and Demi had an 'open relationship' and that he was not in fact cheating. Now I can tell all the facts about how Ashton really was, and hopefully people will believe my side of the story."

Demi Moore will divorce Ashton Kutcher, her husband of 6 years ... and she's strongly suggesting it's because of the cheating scandal.

Demi says, "as a woman, a mother and a wife, there are certain values and vows that I hold sacred, and it is in this spirit that I have chosen to move forward with my life."

Ashton just tweeted, "I will forever cherish the time I spent with Demi. Marriage is one of the most difficult things in the world and unfortunately sometimes they fail" -- though it's unclear if this message was approved by his Twitter team.

Demi and Ashton made headlines in September after a 22-year-old woman named Sara Leal claimed she had unprotected sex with him in San Diego.

Leal claimed Ashton told her he was "separated" from Demi at the time of the alleged affair.

A photographer who claims to have had a run-in with Demi Moore yesterday has filed a battery report about the incident ... TMZ has learned.

Law enforcement sources tell TMZ ... the photographer (who was not TMZ) claims Moore struck him as he tried to shoot her yesterday. We're told it's unclear where Moore allegedly struck the photog, but he displayed no visible injuries.

Judging from the photos of the incident ... it appears the pap was way too close and in her face.

According to our sources, the West Hollywood Sheriff's Department will be given the complaint and investigate.

With no Ashton in sight, Demi Moore hit up Sarah Silverman's comedy show in L.A. Thursday night with some friends -- and she even brought her wedding ring along for the ride.

Demi Moore looked to be in desperate need of a good meal when she hit the N.Y. premiere of her new movie last night ... and according to Joan Rivers, it's because Demi BARELY ate anything on her flight in from L.A.

Joan was on the same flight as Demi ... and after she got off the plane, Rivers sold out her co-passenger to the paparazzi ... telling them that all Demi ate on the 6-hour flight was an apple ... and some water.

By the time Demi hit the red carpet ... it was Moore who was feeding the media, by sporting her wedding ring ... despite rumors that her marriage to Ashton Kutcher is on the rocks.

The moving truck that supposedly took stuff from Ashton Kutcher's house yesterday didn't go there at all -- TMZ has confirmed.

The photo agency that distributed the picture claimed the van went to Ashton and Demi's place, but the couple's rep tells TMZ, the van wasn't at their house ... in fact, it wasn't even on their street.

A moving truck went to Ashton Kutcher and Demi Moore's house in L.A. yesterday ... according to the photo agency that shot this pic.

Ashton Kutcher and Demi Moore spent some quality time TOGETHER in Santa Barbara this weekend ... during a quick camping trip in Santa Barbara with a few of their close friends.

Amidst a tornado of divorce rumors, the couple tried to escape to Cachuma Lake on Sunday ... joined by their Kabbalah instructor Yehuda Berg and Ashton's friend Eric Buterbaugh.

During the trip the gang was seen chatting beside the campfire. The very next day, the all got in their cars and went their separate ways.

Monday, Ashton fired off a few tweets about his wife, saying, "Big night for TV #twoandahalfmen Bears vs Lions and @mrskutcher's 5. My tivo might explode."

He later congratulated Demi on her TV movie, writing, "@mrskutcher good luck tonight! you should be proud."

Just two days before the camping trip, the couple was reportedly spotted together at Kabalah center in L.A. to celebrate Yom Kippur -- the Jewish day of atonement.

Ashton Kutcher's anniversary celebration sans Demi Moore was no big deal -- and to prove it, Ashton ventured out near a Hollywood motorcycle dealer yesterday ... proudly displaying his wedding ring.

Silver lining.

TMZ has obtained photos of Ashton Kutcher partying his face off on his 6th wedding anniversary last weekend -- problem is ... Demi Moore was 3,000 miles away.

Sources tell us, Ashton -- who married Demi on September 24th, 2005 -- was burning the midnight oil at FLUXX nightclub in San Diego early Saturday morning ... while Demi promoted her new Lifetime movie in New York.

But they're Ashton and Demi -- plenty of couples spend their anniversaries apart ... partying ... with strangers ... right?