Mrs Prestidge serenaded the public with her friend Adrian Mann, of Dunedin.
Mr Mann, who owns Alexander Pianos, restored the fire-engine-red instrument.
The pair were inspired to play for the public after attending the Royal Dunedin Male Choir on Sunday.
``It was just such a good concert I said to Janice, we should busk one day.''
While Mrs Prestidge initially thought she was ``far too old to busk'', taking the piano outdoors had been ``really quite a lot of fun''.
Some of the public appeared moved by the songs which were mainly 1920s and 1930s numbers, she said.
``One woman came and gave me a big hug because her mother and father used to listen to this music.''