That was a probably one of my top five episodes, that one.

The filming was all split. They were using a double, but I did all of my dialogue back and forth to the double, with myself.

[To do] all of the angles it went through, I had to time out. The camera [would] move, I'd watch the movement of myself while doing it, and get that down, [so that] actually playing the other, Angelus part, [I'd] understand his movements.

There was a technical challenge to that aspect of it. It took a while. It was a hard episode to shoot.

(Interview with David Boreanaz)