I assume that those responsible for casting couldn`t actually find a genuine Irish actor with a genuine Irish accent, so as has happened so many times before we get lumbered with actors whose attempts at creating a regional accent which is unnatural to them, is so poor as to be laughable. If a character is Irish surely it would be preferable to employ a genuine Irish actor, irrespective of his/her star status, rather than a "name" who makes a mockery of the accent they attempt to mimic! So many films have lacked quality because of dire attempts by so-called stars to speak an accent which they simply cannot do. Time to give those actors to whom a regional accent comes naturally, a chance to become stars instead!