Question: Iarla Ó Lionáird sang "Casadh an tSugain" in a 2015 film based on a novel by what author?
Sentence (from "Iarla Ó Lionáird"): He appeared in the 2015 film "Brooklyn" singing an a cappella version of the Irish folk song "Casadh an tSugain".
Relevant evidence: Yes