The three will perform with their bands before singing together
Three singers called Fiona MacKenzie, who come from the same Scottish island, are to perform on the same night.
Fiona "Gress" MacKenzie and Fiona "Bosie" MacKenzie contacted each other via internet site MySpace.
They then got in touch with Fiona "Alba" MacKenzie - a singer and guitarist who is also a presenter on Gaelic digital channel BBC Alba.
All three are from Lewis in the Western Isles. They will appear at Eden Court in Inverness next month.
The show called Would the Real Fiona MacKenzie Please Stand Up will see them play with their own bands before later singing together.
Fiona "Gress" has been described as Kate Bush meets Bjork. She launched her debut solo album, Elevate, at Scotland's winter music festival Celtic Connections last year.
Fiona "Bosie" writes folk songs with jazz guitarist Graeme Stephen. Their song Live In a Tree was recently the runner-up in the folk category of the UK Songwriting Contest.