Accidental overdose: Heath Ledger died after consuming a cocktail of prescription drugs

"Mr. Heath Ledger died as the result of acute intoxication by the combined effects of oxycodone, hydrocodone, diazepam, temazepam, alprazolam and doxylamine," medical examiner's spokeswoman Ellen Borakove said in a news release.

The drugs are the generic names for the OxyContin painkiller, the anti-anxiety drug Valium, Xanax, an anti-anxiety drug, and the sleep aids Restoril and Unisom. Hydrocodone is another name for ibuprofen.

The statement continued: "We have concluded that the manner of death is accident, resulting from the abuse of prescription medications."

The news comes as Ledger's former fiancée and Brokeback Mountain co-star Michelle Williams arrived in Australia for the actor's funeral with their 2-year-old daughter.

Mourning: Michelle Williams and daughter Matilda, pictured here last year, have arrived in Australia for the actor's funeral

The 27-year-old Williams and Ledger became a couple during filming of the gay romance "Brokeback Mountain" in which they costarred as husband and wife.

They later moved to New York, and had Matilda, who was born October 2005.

In a statement released last week, Williams said: "My heart is broken."

Of the couple's daughter, she added: "I am the mother of the most tender-hearted, high-spirited, beautiful little girl who is the spitting image of her father.

"All that I can cling to is his presence inside her that reveals itself every day.

"His family and I watch Matilda as she whispers to trees, hugs animals, and takes steps two at a time, and we know that he is with us still. She will be brought up in the best memories of him."

Earlier Wednesday, a handful of young people in casual wear were seen entering or leaving the house of Ledger's mother, Sally Ledger-Bell, without speaking to reporters waiting outside.

Ledger's parents and other close relatives arrived Tuesday in Perth after spending nearly two weeks in the U.S. immediately following his death.

Condolences: flowers continue to arrive at the Ledger family's Perth home

They are reportedly planning a private service in Perth and will either bury his body or inter his cremated remains in the city.

There was no indication that Ledger's remains have arrived in Australia. There was no sign of activity at the family's plot in Karrakatta Cemetery Wednesday.

Ledger, who was nominated for an Oscar for his role in "Brokeback Mountain," died in his New York City apartment Jan. 22. He was 28.

Buxbaum has said the family wants to keep funeral arrangements private, and Williams has requested privacy for those in mourning.

Ledger's "Brokeback Mountain" co-star Jake Gyllenhaal also plans to attend the funeral, according to local media reports.

As Ledger's hometown prepared for his funeral, residents of the idyllic and isolated city in the southwest corner of Australia expressed sadness at his sudden death - and outrage at rumors that he was a drug user.

Much of that speculation was fueled by video footage showing Ledger at a Hollywood hotel party where drugs were being taken two years ago.