I saw an interview where Saorise Ronan explained that every film she makes, she does a different accent than her own, especially if she’s playing an Irish character like she did in Brooklyn.
This interested me and I wondered what her American accent would sound like…a lot of times when non-American actors do American accents you can tell they’re fake. I found the below clip of her doing a wide range of accents (why the guy had her say “we are never ever getting back together” over and over again, I have no idea), but her American is particularly good/hilarious.