Thank you for the commit!!

It looks like he is Welsh and it looks like a lot of Welsh people don't consider themselves British, although they may technically be British citizens. That said, he also renounced his British citizenship in favor of US citizenship, so seeing as how is not even technically British anymore, that is probably why he isn't on the Wikipedia list of British actors in the first place.

I can't believe I'm commenting on this thread, but (as someone who has been through the process, albeit without the knighthood) the renunciation of citizenship is more pro forma than anything else. You literally say the words "I renounce all foreign princes and potentates", but you're allowed to keep your old passport (unless you're from a country like China that doesn't allow dual citizenship). Technically, dual nationality might be a reason to strip you of US citizenship later; in the past, no-one has worried about that (the standard being that unless you're actively fighting in a foreign military against the US, dual nationality is OK) but in these days, who knows. Anyway what up github pull request thread

This surprises me, he's often referred to as British or Welsh, in Britain and elsewhere, regardless of actual citizenship.

Looking further, he took US citizenship in 2000, but apparently said: "I have dual citizenship; it just so happens I live in America."

https://en.wikipedia.org/wiki/Anthony_Hopkins#Personal_life

British Consulate officials in Los Angeles said Hopkins could continue to use his title in Britain and would still be recognized as a British national.

http://articles.chicagotribune.com/2000-04-13/news/0004140257_1_citizenship-renounced-british-consulate-officials