Reality star Anna Nicole Smith died Thursday after collapsing at a South Florida hotel.

The former Playboy Playmate, 39, was found unresponsive Thursday in her Seminole Hard Rock Cafe Hotel and Casino room in Hollywood, Fla., police said.

Edwina Johnson, chief investigator for the Broward County Medical Examiner's Office, said the cause of death was under investigation and an autopsy would be done on Friday.

Dr. Joshua Perper, the chief Broward County medical examiner who will perform the autopsy, said if her death was from natural causes, the findings would likely be announced quickly. He cautioned, however, that definitive results could take weeks.

"I am not a prophet, and I cannot tell you before the autopsy what I am going to find," he said.

Seminole Police Chief Charlie Tiger told reporters that Smith's nurse — who was the only one with her at the time — called paramedics at about 1:38 p.m. EST after finding that Smith was unresponsive in her sixth-floor hotel room.

Local streets were closed off just after 2 p.m. EST to rush Smith to Memorial Regional Hospital in Hollywood, which was three miles away.

Police were informed of the star's death at about 2:45 p.m., and it wasn't being treated as a crime at that time, Tiger said.

Video: Police Presser

He said Smith's bodyguard administered cardiopulmonary resuscitation about an hour before she was declared dead.

Smith's boyfriend, Howard K. Stern, 38, was with her when she died at the hospital, her attorney Ronald Rale told FOX News.

Rale told The Associated Press that he had talked to Smith on Tuesday or Wednesday, and she had flu symptoms and a fever and was still grieving over her son Daniel Smith, who died at age 20 in September three days after her daughter, Dannielynn, was born.

"Poor Anna Nicole," he said. "She's been the underdog. She's been besieged ... and she's been trying her best and nobody should have to endure what she's endured."

Stern told "Entertainment Tonight" that Smith's temperature was running high Wednesday night, and that the couple had been in Florida shopping for a new boat.

Paternity Suit

Smith had been embroiled recently in paternity dispute with her ex-boyfriend, Larry Birkhead, 32.

Stern says he is the father of Smith's infant daughter. But Birkhead claims he's the father, and has sued to demand a paternity test.

Last month, a judge in the baby dispute temporarily blocked an order forcing Dannielynn to undergo paternity testing.

Rale, who had been representing Anna Nicole in her paternity battle with Birkhead, said Thursday that an emergency court hearing scheduled for Friday at 11:30 a.m. EST regarding the paternity testing of Dannielynn will go on as scheduled.

Rale said Stern is very distraught and unable to speak publicly right now. He also said Smith was a great mom who loved her kids and that she was under a lot of stress worrying about the paternity situation and the fate of her daughter.

Birkhead's lawyer, Debra Opri, said Birkhead is "devastated" by Smith's death.

"He is inconsolable, and we are taking steps now to protect the DNA testing of the child. The child is our number one priority," she said.

But she also said they would move to get Smith's DNA tested as soon as Friday.

"We’re moving in an emergency order tomorrow for the DNA testing of Anna. We’re also going to wait with the understanding that the autopsy is not going to show what the spin doctors are saying out there, that she died of a rare flu.

"Larry Birkhead is the father and he wants his child," she told FOX News. "He doesn’t want another death. We had serious concerns and we brought it to the judge’s attention. Anna Nicole Smith is dead at the age of 39 because of her lifestyle. I do not want that child anywhere near Howard K. Stern."

Smith checked into the Betty Ford Clinic in 1995 for addiction to prescription painkillers and alcohol. While she said she was rehabilitated, she continued to be known for loopy behavior.

"Undoubtedly it will be found at the end of the day that drugs featured in her death as they did in the death of poor Daniel," said a former attorney for Smith in the Bahamas, Michael Scott.

Another former Smith attorney, Lenard Leeds, told TMZ.com that it was no secret that Smith "had a very troubled life" and had "so many, many problems."

Grieving Mom

An American medical examiner hired by the family, Cyril Wecht, said Smith's son Daniel had methadone and two antidepressants in his system when he died in September. Low levels of the three drugs interacted to cause an accidental death, Wecht said.

Last month, Bahamian officials agreed to conduct a formal inquest into Daniel's death. The inquest was scheduled for March 27.

More than 20 witnesses will be called to testify, including one who allegedly insists that Stern gave Daniel methadone before he died. Stern was in the room at the time of Daniel Smith's death.

The same witness also will tell officials that after Daniel's death, Stern flushed the remaining methadone down the toilet, TMZ reported. Stern has denied this report.

Smith was also going to be among the witnesses required to testify before the jury inquest, Chief Magistrate Roger Gomez said.

Smith and Stern exchanged vows in a non-marriage "commitment ceremony" 18 days after Daniel died on Sept. 10.

Early Years

Anna Nicole Smith was born Vickie Lynn Hogan in Houston, Texas, on Nov. 27, 1968.

As a teenager, she worked at a fried chicken restaurant, and married Billy Smith at age 17 in 1985. The same year she had son Daniel Smith, but then divorced Billy and became a single mother in 1987.

Smith worked a string of minimum-wage jobs before turning to stripping. She met oil mogul J. Howard Marshall II in 1991 in Houston at a nightclub, where he was a frequent patron and she worked as an exotic dancer.

The gorgeous, voluptuous blonde entered her photos in a search contest and made the cover of Playboy magazine in 1992, captivating readers with her Marilyn Monroe looks. She became Playboy's Playmate of the Year in 1993. She was also signed to a contract with Guess jeans.

Smith married Marshall, 63 years older than she, on June 27, 1994. She was 26, he was 89. The age difference sparked criticism and speculation, but Smith defended her marriage.

Smith claimed to be very close to the aging billionaire and that while they loved each other, they married for companionship and his desire to support her rather than the conventional husband and wife lifestyle.

Marshall II died in 1995 at age 90, setting off a feud with her former stepson, E. Pierce Marshall, over whether she had a right to his estate.

A federal court in California awarded Smith $474 million. That was later overturned. But in May, the U.S. Supreme Court revived her case, ruling that she deserved another day in court in her battle with her former stepson.

The stepson died June 20 at age 67. But the family said the court fight would continue.

Smith's ballooning figure and up-and-down weight was also a subject of public fascination. But she lost a reported 69 pounds and became a spokeswoman for TrimSpa. Smith and TrimSpa were sued in a class-action lawsuit last Thursday, alleging their marketing of a weight-loss pill is false or misleading.

Other than small roles in movies like "Naked Gun 33 1/3" and "The Hudsucker Proxy," Smith has appeared mostly in soft-core porn movies. From 2002-2004, E! Entertainment television gave Smith her own reality show called "The Anna Nicole Show" in the spirit of "The Osbournes."

Wayne Munroe, the Bahamian lawyer who has overseen the aftermath of her son's death, had kind words to say about Smith in response to the news of her death.

"From my professional exposure to Anna Nicole, I can say she was always personable, down to earth and driven. All in all, a joy to have as a client."

Click here to read about Anna Nicole Smith's litigation history (pdf)