Maggie Gyllenhaal has revealed she was so taken with the English accent she sports for The Honourable Woman, that she used it even when she was not in character.
The American actress, who plays Anglo-Israeli Baroness Nessa Stein in Hugo Blick's BBC drama, had to perfect the cut-glass accent for the role.
"I've done an English accent quite a few times now. I did it in Nanny McPhee Returns and in Hysteria. But this is the first time I've ever felt it was totally in my bones," she said.
"It just felt like it was my voice. I did this thing, which I know is kind of embarrassing, but once I was in work, I just talked in an English accent all day."
However, Maggie - who is mum to two daughters with husband Peter Sarsgaard - admitted she drew the line at speaking to him in Nessa's clipped tones. She said: "I could never talk to him in an English accent. He would just be like, 'What are you doing?'."
The 36-year-old, who grew up in Los Angeles and lives in New York, admitted she could see herself living in the UK.
"I feel like that's really where I ought to be living. I just have to convince my husband," she said. "You know how in some cities you just feel like they welcome you in? I feel that way about London. You make friends easily and get the rhythm of the city."
Maggie said she enjoyed playing someone as complex as Nessa, who witnessed her father's assassination as a child, was held hostage in Gaza as a young woman, and also harbours a dark secret from her past.
"She's so much more alive than I am - than anyone is, really. It's nice to be in her skin," she said. "She's confident and intelligent and graceful, but she's also broken and confused and scared."
:: The Honourable Woman begins on BBC One on July 3.