I'm completely Americanized - I have an American accent, an American wife - but a residue of me is foreign.
I think most British people who say they can do an American accent are so bad at it. I find it excruciating. I find it excruciating the other way around, too.
When I sing along with Britney Spears I will sing in an American accent. But eventually I found my own voice. My songs are so brutally honest, it would be alien to sing in any accent other than my own. Don't get me wrong - I can imitate singers. I can do bar mitzvahs and weddings.
My grandma said - when I was really young and I'd sing along to the radio - why do you sing in an American accent? I guess it was because a lot of the music I was listening to had American vocalists.
I've played American characters so many times now, it's so natural to me. But when I play American, I stay in the American accent from the minute I get the job till the minute I wrap.
I often find during a day of shooting I will speak in an American accent all day long when I'm doing dialogue. At the end of the day, it often takes an effort when I'm talking to my fiancee to bring my English back just because you're so used to speaking that way.
I lived in America for a long time before I started working as an actor. Some actors show up on set and have never done an American accent before, so they rely on a slew of technical mechanisms. Part of what makes an accent is understanding why people speak that way - you have to understand the culture.
I could do an American accent, if I were immersed in the accent, meaning if I were living back in Los Angeles and rehearsing and auditioning the whole time.
Most Australians who've got an ear can do an American accent because we grow up listening to them on television and in movies.