Most actors try to get inside their character’s head and may even alter their physical appearance to match (think Robert DeNiro in Raging Bull). Not NPH. He works “from the outside in”:

When we were filming Dr. Horrible, I was imagining watching it in my living room. When I’m co-hosting with Kelly Ripa, I’m not thinking Neil the Actor. I’m thinking, Housewife, ironing clothes, 11 o’clock. What kind of thing does she want to see?

This floored me. I’ve studied cinema and acting for much of my life (as a hobby, mostly) and never heard of this self-visualization technique. What he’s really doing is thinking of his audience members and what they’d respond to. And then packing a performance with them in mind.

Considering his success, I’d say it’s working for him.