Most convincing non Irish actor in an Irish role.

Theres always threads about worst Irish accent in a film,Tom Cruise in Far And Away and the like but are there any instances of outsiders convincingly portraying an Irish character on screen?Now it can be a bit tricky defining who is and isin't Irish in the case of someone like Aidan Quinn who was born in the States but spent a considerable amount of their childhood in Ireland.So for arguments sake lets say someone who did not grow up in the old sod(that probably rules out Anjelica Heuston,I know).First choice for me is Ian Harte,a scouser,whos played Cork in Michael Collins,Monaghan inThe Butcher Boy,Belfast Loyalist in Nothing Personal and Dub in Thousands Are Sailing,pretty convincingly each time.