Some 53 percent of the world’s wealthy expect to still be alive at 100 years of age.

“The idea of living a century was once confined to science fiction,” said the UBS report, titled The Century Club. “But no longer. For the world's wealthy, living a 100-year life is not an outcome they consider a mere possibility. It's one they expect.”

In Asian countries, about half think they will reach that age. Only 30 percent were so confident in the US.

Statistics from the US Social Security Administration showed that in 1930, the average life expectancy for American men was only 58. Fifty years before that, they could expect to live to around 35 years old.

While the millionaires are confident about their longevity, more than 70 percent are worried that their health will deteriorate over the next 10 years. Healthcare costs topped their list of concerns, with 52 percent of investors anxious about rising medical expenses.

The rich are more than willing to sacrifice money for extra longevity. Nine out of 10 wealthy people agreed that “health is more important than wealth.”

Asked by UBS how much of their fortune they’d be willing to give up “to guarantee an extra 10 years of healthy life,” those with $1-$2 million in net worth said could give up a third of their nest egg. Investors with more than $50 million were willing to part with almost half of their fortune for an additional decade of life.

Overall, 77 percent agreed that working as long as possible was good for your health. The sentiment was particularly strong in Asia and Switzerland but far less so in the US and the UK.