A British, American, Australian Coincidence

In 1985 I was a British Army officer serving on an exchange with the Australian Army in Queensland. Just before my wife and I returned to the UK we took some friends out to a meal. The owner of the little restaurant asked if we would like a girl who played the zither to play during the meal, to which we agreed. We arrived early for the meal to make sure all was OK and the girl, an American, arrived to set up. I chatted to her and during the course of the conversation I said that I had been to the USA only once in 1977 when I had visited the two friends I knew there - one living in LA, the other in Washington DC. As she told me that she lived in Washington and the conversation was flowing I told her that my friend worked for the National Geographic magazine. She replied that she knew a number of people who worked for the National Geographic and asked me his name. I told her that it was Olly xxxxx to which she replied that she knew Olly and his wife really well. I am not a statistician but the odds on my meeting an American in Australia who knew one of the two people I know living in the USA must be astronomical.