Eleven years ago Anna Nicole Smith died the same way her son did, and it's no coincidence.

The final months of Anna Nicole Smith‘s life contrasted moments of sheer joy with unbearable heartache.

In September 2006, the former Playboy model welcomed her daughter into the world. Just days later, her son Daniel – while visiting her and his new half-sister in hospital – died, aged just 20. The baby was named Dannielynn in his memory.

Five months later on 8 February, Anna Nicole Smith died the same way her son did, of an accidental overdose of prescription medication.

However, more than just a tragic coincidence, people close to Smith have suggested the mother and son’s deaths were closely linked.

Daniel was born in 1986, the product of Smith's first marriage to Billy Wayne Smith, who she wed in 1985 when the pair were 18 and 17 years old. This was back when Anna Nicole was still going by her given name, Vicky Lynn Marshall.

Smith's close relationship to her son has been spoken about by many, including her former partner, attorney and agent Howard K Stern.

In a People magazine interview published just weeks after her death, he described the pair's relationship.

"Anna and Daniel were inseparable. Daniel was without question the most important person in Anna’s life. From the time I met her, everything was for Daniel," he said.

"I would say that physically, she died last week, but in a lot of ways, emotionally she died when Daniel died."

LISTEN: Playboy founder Hugh Hefner bought a burial plot next to another famous cover star Marilyn Monroe, cementing him as a creep for eternity. (Post continues after audio.)

There's no doubt her son's death was a huge blow to the former reality TV star - like the loss of any child to a parent is. But her former doctor has recently suggested her grief may have been amplified by thoughts that she helped to cause it.

Dr Sandeep Kapoor, who was actually charged and later acquitted of offences related to Smith's prescription drugs supply, shared his thoughts on the case of the young man's death on Fox News.

Toxicology reports showed Daniel had antidepressants Zoloft and Lexapro in his system, which proved deadly combined with painkiller methadone - which Dr Kapoor suggested he may have taken from his mum's stash.

"Daniel was a sweet, young boy. Younger than his age," he said.

"I thought at the time no one had prescribed him methadone, as far as I know. I didn’t prescribe [him] any methadone. Maybe perhaps it was Anna’s methadone."

Dr Kapoor imagined Smith knew this to be true.

"And I guess she kind of knew that. That added to her grief, her guilt. Because what happened shouldn’t have happened," he told Fox News.

"It just added so much to her grief, that maybe it was her medicine that caused his death."

And maybe that's part of the reason why Smith, who Dr Kapoor said had been stringent while following "very strict guidelines" of pain medication during her pregnancy with Dannielynn, somehow managed to take a fatal overdose five months later.

At least that's what Dr Kapoor thought, suggesting grief played a role in her death.

"She was horribly upset and seemed to want to live in a world where he wasn’t dead," he said.

"It was a denial world. Even though she really wanted to be around to raise her daughter, she couldn’t overcome this loss."

Anna Nicole's final days.

According to investigators, Smith's final days were likely spent in a drug haze. Her partner Howard Stern said she had suffered flu-like symptoms since they arrived at the Seminole Hard Rock Hotel and Casino in Hollywood on 5 February and was taking anti-viral medication to treat it.

Stern said that on the morning of  8 February 2007, he had helped his partner to the bathroom and then she went back to bed, where to his knowledge, she stayed until he left the hotel around 11am. Two hours later, her personal nurse, who had been travelling with the couple, discovered her unconscious and called for emergency services. CPR was administered and paramedics arrived a short time later, but the 39-year-old was pronounced dead at a nearby hospital at 2.49pm.

An autopsy later revealed that Smith had in her system a combination of sleeping medication chloral hydrate - labelled the "major component" in her death, the cough medicine Benadryl and three benzodiazepines, Clonazepam, Lorazepam and Diazepam, the latter known commonly as Valium. However, police discovered dozens of different prescriptions and pills in her hotel room on the day of her death.

The legal fallout after her death.

Dr Kapoor and Stern, along with psychiatrist Dr Khristine Eroshevich, were later charged with unlawfully prescribing controlled substances and obtaining fraudulent prescriptions and tried in court. Dr Kapoor was acquitted of all charges in 2010.

Stern, however, was first found guilty of two counts of conspiracy (to supply her with drugs), before his conviction was dismissed by another judge a year later. That judge found that although Stern had used a fake name to obtain prescription medication for Smith, it was to protect her privacy, not to harm her.

Meanwhile, Dr Eroshevich, was first found guilty of conspiracy, but then only obtaining drugs by fraud. She served no jail time, but did have her medical licence revoked.

However, this wasn't the only legal battle to come out of Anna Nicole Smith's death.

Check out this weeks @usweekly for all the fun photos and a recount of our celebration of Anna Nicole’s @annanicolesmith1 birthday as we return to The Bahamas. #thathairtho #larrybirkhead larrybirkhead #dannielynn #annanicole #annanicolesmith #usweekly

A post shared by Larry Birkhead (@larryanddannielynn) on Nov 30, 2017 at 8:16am PST

In the three months after she died three men claimed paternity of Smith's daughter Dannielynn, including Stern, who was listed on her birth certificate. However, in April 2017, after a DNA test, Smith's former boyfriend Larry Birkhead was found to be her father and was granted custody of the child.

Since then, single father Birkhead has tried to keep her mother's memory alive for Dannielynn, taking her to visit her mum's grave and the place she loved, the Bahamas.

"It's tough raising a little girl without a mum," he said while on The Steve Harvey Show in 2016.

"It's different than a normal situation. I make it as normal as I can."