British?

Apparently he's pretty good with accents since people often say something to that effect. He doesn't always have an American accent in movies, but maybe you haven't seen those where he doesn't (like The Prestige, for instance). But he has lived in the US since he was a teenager - and says himself that it would be worrying if he couldn't manage an American accent by now - correct on one hand, but also his typical modesty on the other, since it's not like he just constantly uses one American accent, but multiple different ones, and so he needs to keep learning new accents anyway.

Btw, I don't know how one supposedly looks or acts British... could you elaborate on what you mean? I'm genuinely curious what you had in mind.

you know like how they are and act in real life like in interviews, but i guess it's mostly of the accent and because i have this image of him from movies and the characters he plays, but then again i also thought many other British actors were American like Michael Fassbender. I guess it's just me.

you know like how they are and act in real life like in interviews

No, I don't - that's why I asked (for specifics, and that didn't clarify your point at all) since I don't know what you meant by it. I'm neither American nor British myself, I've been to both places, know people from both places, and I don't know how one "acts British" or "acts American" as there is so much variety. So I also don't see how British actors or American actors are noticeably (or not at all like you were saying) British or American in their behavior or something. I asked out of genuine curiosity how someone else sees that, because I don't, and I'd like to know what people mean by it.

It certainly isn't just you though, I've seen something similar mentioned before by someone (they didn't specify what exactly they meant, either). Assuming Hollywood actors (if they ever play American characters) are American unless proven otherwise, is actually very common. Tons of people over the years (and still) have been amazed when they learn Bale is not American. Or Hugh Laurie or many others. I'm sure a lot of people just think of Charlie Chaplin and Cary Grant as Americans as well.

I didn't know he was Welsh until last year. Thought he was just regular Brit...

His breakthrough role in Empire of the Sun showcased his British accent and he has played Brits quite a few times since.

When he was promoting the Dark Knight he would use an American accent for those interviews. Dedicated.