Helena Christensen has claimed Michael Hutchence developed a "dark, angry side" after he suffered a brain injury.
The supermodel, who dated the INXS frontman for four years following his split from Kylie Minogue, has broken more than two decades of silence on her life with the Australian rocker.
Speaking candidly in the new documentary, Mystify: Michael Hutchence, Helena confessed she was head over heels after first meeting Michael, and described him as her "perfect match".
"(It was) total mental and physical chemistry," she said.
However, his personality allegedly changed in 1992, after he was assaulted by a taxi driver and hit his head on the pavement.
"He was unconscious and there was blood coming out of his mouth and ear," the Danish model recalled. "I thought he was dead."
Michael's injuries meant that he lost his sense of smell, but he also developed a "dark and very angry side" of himself.
"We got to the hospital and he woke up and was aggressive," Helena remembered. "They were trying to make him stay but he was physically pushing them away."
While the 50-year-old - who went on to date The Walking Dead star Norman Reedus and later, Interpol frontman Paul Banks - tried to support her boyfriend through the terrifying time, she was troubled by his worrying mood swings.
"Something drastic happened. I was deeply sad, confused and bewildered, but at the same time it couldn't have continued that way," Helena confessed.
The couple split in 1995, and Michael began dating British TV presenter Paula Yates. The musician was found dead in his Sydney hotel room in 1997, with an inquest confirming he had committed suicide.
Paula, who shared daughter Tiger Lily with the late rocker, died three years later.