A new HBO documentary will examine the mysterious death of Hollywood star Brittany Murphy and her relationship with her British husband.

Murphy, whose films included Clueless, 8 Mile and Just Married, died aged 32 in 2009.

Her cause of death was ruled an accident, with a coroner blaming a combination of pneumonia and over-the-counter medications she had taken, but questions remain.

Two-part documentary series What Happened, Brittany Murphy? features interviews with Murphy’s former co-stars and shines a light on her marriage with London-born screenwriter Simon Monjack.

A trailer accuses Monjack of repeatedly lying, including made-up claims he had survived terminal brain cancer and dated Madonna and Elle MacPherson.

To add to the mystery, he died aged 40 less than six months after Murphy at the same Los Angeles house under similar circumstances.

“Brittany was so wonderful,” Kathy Najimy, who worked on animated series King Of The Hill with the late star, said in the trailer.

Brittany Murphy and husband Simon Monjack
Brittany Murphy’s marriage to Simon Monjack will be examined in a new HBO documentary (HBO Max/PA)

She said Monjack “came along” when the star was suffering a “little dip” in her personal life.

Najimy added: “I think that’s where her judgment was muddled, and she became prey. We all were scared and freaked out. Like, ‘Who was this guy?'”

The documentary follows Murphy’s struggles in Hollywood. She had been one of the industry’s brightest rising stars but dropped in weight and changed her image after feeling pressured to land roles.

Brittany Murphy
Brittany Murphy’s life and career are the focus of a new HBO documentary (Ian West/PA)

Elsewhere in the trailer, doubt appears to be cast on the narrative surrounding Murphy’s death.

“A healthy 32-year-old doesn’t just die,” a contributor says.

Directed by Cynthia Hill, What Happened, Brittany Murphy? features new archival footage and interviews with those closest to the actress.

Producers say it “goes beyond the tabloid rumours to examine the impact of Hollywood’s sexism on her struggles, as well as lingering concerns about her relationship with” Monjack, who married Murphy in 2007.

Both episodes of the documentary will debut on HBO Max on October 14. A UK release date has not been announced.