Her dad is English (actor Will Keen) and her mum is Spanish (MarÃa Fernández), she holds both British and Spanish passports, and spends more time in the UK than the US. So why would her accent be anything other than British when she speaks English? Look up the word bidialectal in a dictionary. Gillian Anderson and John Barrowman are 2 others who are the same having been born and raised in the UK before moving to North America. I don’t know why it’s so confusing to understand this. She clearly speaks with an English accent when speaking English with her own voice. And any English person will recognise it as genuine rather than say Spike in Buffy or RDJ in Sherlock Holmes.