Montana Fishburne faked a suicide attempt and it was all caught on video ... TMZ has learned.

Sources tell us that last August, Montana's dad,
Laurence Fishburne, was so concerned about his daughter's well-being that he had a private investigator follow her around. The investigator shot video of Montana drinking what appeared to be bleach.
Turns out, Montana faked the whole thing. Sources say she found out a P.I. was videotaping her and drank the bleach "to put on a show."
The tape has become relevant in the ongoing criminal assault case against Montana because her lawyer,
Shawn Chapman Holley, had sent the tape to the prosecutor
to demonstrate her client's troubled mental
state and help get a plea deal that involved rehab, not jail time. The prosecutor agreed to the deal, but has since disavowed it and wants her to do jail time.
The prosecutor argues in legal papers, obtained by TMZ, that the video "was just a ploy by the defendant to manipulate the People to offer a more lenient sentence."
But we've learned, shortly after sending the video to the prosecutor, Holley learned it was fake and actually notified the prosecutor everyone had been duped by it.
Holley is asking the judge to enforce the original deal -- rehab and no jail. The prosecutor is steadfast and does not want to honor that deal.
Montana Fishburne says she's heading to an inpatient facility in California for all the right reasons .... because according to the recently minted sex tape star, she's "just trying to get my life together."

As
we first reported, Montana -- who's awaiting trial for allegedly beating up her boyfriend's ex -- has decided to spend at least 30 days at a facility in Southern California to work out some issues.
Montana Fishburne -- aspiring
sex tape star and daughter of
Laurence Fishburne -- is checking herself into an inpatient facility that specializes in anger management, behavioral problems and mental illnesses ... sources tell TMZ.

We're told the facility is in Southern California and Montana will be there at least 30 days. Sources say part of Montana's stay will be devoted to anger issues, but she'll also undergo diagnostic tests to determine if there are underlying behavioral or mental issues.
Montana is
currently awaiting trial for allegedly beating up the ex-girlfriend of her current boyfriend.
Sources say Laurence Fishburne is unaware that Montana has decided to seek help.
Montana's lawyer,
Shawn Chapman Holley, could not be reached for comment.
Montana Fishburne claims she finally broke the ice with her dad after
releasing that hardcore sex tape -- telling us, the formerly feuding father-daughter combo are "working on things."

TMZ ran into Montana in L.A. yesterday, where she told us her dad
Laurence Fishburne is coming to terms with the whole my-daughter-is-a-porn-star thing ... claiming, "Me and my dad are great."
As we first reported, Montana claimed Laurence had stopped talking to her over her XXX career move -- but according to our sources, it didn't stop him from paying
Montana's legal bills.
Montana Fishburne just plead not guilty to assault with a deadly weapon and false imprisonment -- after she allegedly beat the crap out of her boyfriend's ex-girlfriend earlier this year.

Fishburne -- who was not in court in L.A. today but was represented by
Lindsay Lohan's lawyer
Shawn Chapman Holley -- has previously pled not guilty to one count of battery.
As we first reported, Montana and her boyfriend
Jerome Greene were arrested after they allegedly barged into the alleged victim's home back in February ... and then forced the woman into the bathroom and beat the daylights out of her.
Greene has already pled no contest in the case to domestic violence.
Montana's next hearing is scheduled for September 28.
Laurence Fishburne is secretly funding his
daughter Montana's legal defense ... sources tell TMZ.

TMZ
broke the story ...
Montana Fishburne claimed daddy Laurence wanted nothing to do with her after she decided to enter the world of porn.
But now we're told ... It was Laurence who hired Montana's lawyer,
Shawn Chapman Holley, to represent her in an ongoing
assault with a deadly weapon case ... in an attempt to help her out and get her life back on track. We contacted Holley -- she refused to comment.
Our sources say Laurence continues to foot the bill for Montana's defense.
So, Montana, who loves ya?
We took your questions on everything -- including
Lindsay Lohan possibly being released from rehab tomorrow,
Rachel Uchitel wanting
Tiger Woods back, and
Heidi Montag willing to talk business on her sex tape release.

Plus:
Laurence Fishburne secretly funding his daughter
Montana's legal defense.
We took your questions today on everything -- including
Dr. Frank Ryan's death,
Montana Fishburne claiming
Laurence wants nothing to do with her, and
Method Man getting hit by a projectile at a concert.

Plus:
Tiger Woods alleged porn star mistress
Devon James' paternity case gets dismissed.
Montana Fishburne tells TMZ ... she called daddy
Laurence Monday for the first time since she unveiled her plan to enter the world of porn ... and he was none too happy.

Montana says Laurence told her she is unwelcome in his life and wants nothing to do with her ... at least for now. According to Montana, her dad said, "I'm not going to speak with you 'till you turn your life around." Laurence was referring to his daughter joining the ranks of
Vivid Entertainment as a porn star.
Montana says Laurence added, "You embarrassed me."
And this parting shot. According to Montana, Laurence said, "You used your last name. No one uses their real name in porn."
Montana Fishburne officially has plenty more opportunities to piss off her father -- we're told
her first XXX movie was such a hit ... the porn company that shot it just offered her a multi-picture deal.
Vivid Entertainment prez
Steve Hirsch tells TMZ, the first shipment of Montana's porn sold out across the country -- more than 25,000 copies in total -- and we're told even more DVDs were placed on backorder.
According to Steve, Vivid has officially offered
Laurence Fishburne's 19-year-old daughter -- aka "Chippy D" -- a multi-picture deal to cash in on all the success ... although it's not clear how many adult flicks that actually entails.
As we first reported, Laurence's close friends offered to buy up every last copy of Montana's porno for $1 million -- but by then it was too late ... the DVDs had already been sent out.
No word yet if Montana will take Vivid up on their new offer.
For the first time since his daughter released a sex tape,
Laurence Fishburne was seen out in L.A. this weekend ... wearing a shirt that reminded everyone who really deserves the attention in his family.

Fishburne -- who had just performed in a stage production of "
Thurgood" -- was leaving the theater hand-in-hand with his wife
Gina Torres.
As we previously reported, Laurence has not spoken with
his daughter Montana since she announced
her move to do porn ... despite support from her mother
Hajna Moss-Fishburne.