OK he's not a Trad or Folk musician, but he was at the Lisdoonvarna Festival in 1982, and one of his biggest hits was in fact the Irish Traditional Song "Whiskey in the Jar", so I suppose that qualifies him to be included.
Phil performed on the day with a Group called Grand Slam, though he is more famously know as being the frontman for the Irish band - Thin Lizzy. Phil died on 4th January 1986.
Location: Lisdoonvarna, Co Clare.
Photographer: Colm Keating