We have big casting news for the show.
From Variety

Ackles is set to recur as “Sister Jo” in the later part of the 13th season of the CW’s hit demon hunting drama. Sister Jo is described as “a well-known faith healer whose good works attract the attention of someone very, very bad: Lucifer (Mark Pellegrino).” The question she will have to face is whether Lucifer will kill her — or if he has bigger plans for her.

Her first appearance will be in episode 13, “Devil’s Bargain.”

Entertainment Weekly has more on the story.
Here's an interesting Twitter conversation from 2012.
How great for Jensen to have his wife on set! I'm really looking forward to her appearance. What do you think?