Michael Jackson's dependence on drugs became so prominent at one point in the 1990s he often became a “living corpse”, a nurse has said.

Kathryn Buschelle, the long-term partner of one of the singer's surgeons, said Jackson was a persistent user of the sedative Dirpivan.

The drug, also known as propofol, is commonly used to help induce a patient into unconsciousness before surgery and was one of the painkillers found at Jackson's house after his death.

In an interview with The Sun newspaper, Buschelle said Jackson began taking the drug to relieve the pain of skin surgery.

“Michael's obsession with his appearance led to more and more skin treatments and his subsequent addiction to Diprivan led to even more. It was an insane cycle,” she said.

"He was literally burning his skin off and then being knocked out like a zombie. It reads like a horror movie script.

“Towards the end of the 90s he was a dead man walking, that's how zoned out he was."

Buschelle added that Jackson eventually came to request the drug, despite not needing it.

“He would stay a few days, sometimes spending as long as 72 hours under,” she said. “Michael effectively mummified himself. He'd just lie like a living corpse."

Officials found the intravenous anaesthetic during an extensive search of the star's rented home in Holmby Hills in the wake of his death.

Jackson's alleged drug use has become the focus of the police's investigation.

A postmortem last week ruled that there had been no foul play or external trauma in the star's death.

But the cause of death has been deferred while doctors await the results of toxicology tests.

(by Jason Gregory)