"I didn't want to get depressed about it ... and so I thought, 'Wouldn't it be interesting to see what other people born the same day as me are up to? I wonder what their lives are like?"'
It was only an idea for several years, until he lost both his parents within a short time of each other about two years ago.
"I just thought, 'Life's too short.' So I thought to give it a go."
Mr Avis put out a call for "time twins" to come forward. The response was huge, with hundreds of people getting in touch.
However, only a few were willing to be part of his project - to travel out to meet them and document their lives.
In the past few years, he has travelled to various parts of the globe to meet his time twins.
"I met a voice coach in New York, a lawyer and a writer in horticulture in Sweden, an over-35 female body-building champion in Holland and when I went back home to Britain I met a guy who was a drummer in a band."
He also spent some time in Norway and Austria, where he found a woman who made air-conditioning systems but had also represented her country in handball at the Olympics one year.
In a small Italian town, Mr Avis found a time twin was the mayor there.
Mr Avis travels with a film crew and a friend who is helping to write a book about the journey.
He is currently in Australia and was yesterday meeting a time twin at the Sydney Opera House.
He is hoping to come to New Zealand next month in his quest to find more time twins and will then go to Vanuatu, Malaysia and Indonesia.
He said the experience so far had been exciting and humbling, and had opened his eyes to the circumstances and challenges people faced in different countries.
"We're just trying to get a whole different perspective from people of all backgrounds. It's all about meeting people and knowing more about them, yes. But it's also about learning something deeper about cultures."
