Olivia Newton-John speaks about the mysterious disappearance of her ex partner for the first time.

It sounds like a movie script. A famous actress’ ex partner goes on a fishing trip off the California coast, but never returns, sparking rumours he’s faked his own death and is now living with his lover in Mexico.

But for Olivia Newton-John, it’s all too real.

The 68-year-old spoke of the mystery on last night’s episode of 60 Minutes, more than a decade since Patrick McDermott vanished off San Pedro.

“It was very hard, he was lost at sea and nobody really knows what happened,” she told Karl Stefanovic.

Olivia Newton-John still wonders if her former partner is alive. Image: Channel 9.

With multiple sightings of the American cameraman reported over the years and at least one investigator concluding his death was staged, it's inevitable that Newton-John still wonders what happened to her partner of nine years.

"It's human to wonder," she told the programme. "Those are the things in life you have to accept and let go, because whenever you go through difficult times there's always those concerns, but I live on.

"And of course questions come up, that’s human.”

The comments are among the first the actress has made about McDermott's June 2005 disappearance.

The pair had split just months prior and McDermott had recently filed for bankruptcy, with debts totaling $30,000.

None of the other 22 passengers on the boat noticed him go overboard and he was not reported missing until a week later when he failed to show up for a family gathering.

The US Coast Guard launched a frantic, exhaustive search of the area but failed to locate a body.

In November 2008 it was declared that McDermott "most likely drowned".

The same year Newton-John married the man she calls "the love of her life", businessman John Easterling.