The actor met a friendly family while enjoying a sunshine break Down Under with his own relatives in 2003.
The Radcliffes ended up exchanging presents with their hosts, and reveals his parents became lifelong friends with the Aussie clan.
Radcliffe recalls, "I did a press tour of Japan in 2003 and the Warner Bros. present to my family for me doing that tour was to send us anywhere we wanted to go for Christmas. We said, 'Australia please.' So, we arrive on Christmas Day and go to the hotel where the Christmas lunch was being served.
"There's a family sitting opposite who recognise me and come over and chat. They invited us to their house to finish Christmas lunch. It was either that or the hotel room. So we experienced the meaning of Australian hospitality.
"They were really, really sweet. They even nipped out to get us presents. We made some really, really good friends and, to this day, my mum and dad are still in contact with them."