Michelle Pfeiffer and accents...

Is she known for not being able to master accents? I think she's a great actress and have enjoyed many of her performances, however I'm just watching Dangerous Liaisons and she seems to be the only actress not able to pull off the accent she's trying to do. This American twang keeps popping up, making her sound like Effie Trinket off The Hunger Games!
I noticed the same in Stardust!