He's British!

I've never watched an entire episode of House, but I have caught parts of it, and I thought the main character was American. But he's British! In fact, I already knew who he was (Hugh Laurie), but I didn't make the connection: he was on the British show Jeeves and Wooster, which is actually too annoying to watch too often.

Here's a video of Hugh Laurie auditioning for House--you can sort of detect a slight British accent in the beginning, but when he's in character, he sounds like an American, and believe me, I'm American, so I should know what an American accent should sound like. Also, here and in the show, he behaves like an American. So it's not just the accent, but his manner. Bottom line: he's convincing!