Simon Monjack, a British screenwriter who died in Los Angeles Sunday at the age of 40, was scheduled to have bypass surgery this fall, a publicist said.

Monjack was married to actress Brittany Murphy for nearly three years. The 32-year-old "Clueless" and "Sin City" star died last December. Her death was ruled an accident due to pneumonia, an iron deficiency and multiple drug intoxication.

"As far as we know he passed away of natural causes," E! News said Roger Neal, a publicist for Murphy's mother Sharon, told reporters at a press conference Monday regarding Monjack's death.

"He did have a heart condition (and) he was due for bypass heart surgery," Neal said.

"What's been out there on TMZ I don't believe is correct at all; anything that they have intimated is not correct," he added. "He was a man full of life and a man excited about the future."

Some media reports have suggested Monjack died of an accidental drug overdose.

"I loved Simon like a son, and he loved me like a mom. I've lost a son-in-law and a daughter, and I'm devastated," Sharon Murphy said in a statement issued to

Murphy reportedly had been living with the couple at the time of her daughter's death and has since remained as a resident of their home.