Simon Baker: All those times we heard the voice of Red John? That was me.

All those times we heard the voice of Red John? That was me.

TV Guide Magazine: Seriously?
Baker: Yes! In the Season 2 finale, when Jane was captured and Red John did that "Tyger, Tyger" thing with the mask on? That was me. I played both characters in that scene.

TV Guide Magazine: Wow. That's especially trippy considering there was a major theory going around that Jane was Red John. So in a way that turned out to be true!
Baker: That was the reason I did that. There was a point where Bruno was saying, "We don't know who we're going to cast to play [the masked Red John]." I said, "Don't cast anyone! I'll do it." Bruno was, like, "I love it! I love it!" So I put on a mask and did that funny, wispy little voice. And for seasons after, whenever Red John spoke, I had to go record the voice.

More here