‘Supernatural’ Season 12 Episode 3 Spoilers & Promo: Castiel Threatened By Old Foe; Dean’s Worries Mounting

An old foe of Castiel (Misha Collins) is appearing on an upcoming episode of "Supernatural." The character is portrayed by Alicia Witt, who announced the latest "Supernatural" casting news herself.

Witt said on Twitter that she has been in Vancouver, Canada shooting her role on "Supernatural," saying that she "has a relationship with Castiel." The actress added in a follow-up tweet that she "did not specify what *kind* of relationship" her character and the angel have.

TVLine confirmed that Witt's "Supernatural" character is named Lily Sunder, who's an "old enemy" of Castiel. The exact episode where the actress will appear is still unknown.

Prior to her "Supernatural" guest role, Witt appeared on AMC's "The Walking Dead" as the villainous survivor Paula. The actress also had recurring roles on ABC's "Nashville," FX's "Justified," and in Showtime's "Twin Peaks" revival.

In the upcoming "Supernatural" episode titled "The Foundry," Castiel will "begrudgingly partner" with the demon Crowley (Mark A. Sheppard) to hunt Lucifer, whose new vessel is a rock star named Vince Vincente (Rick Springfield). Dean (Jensen Ackles), Sam (Jared Padalecki), and Mary (Samantha Smith), meanwhile, will investigate a "mysterious abandoned house" where "a crying baby leads to death," TV.com reported.

Mary, who was a hunter when she was still alive, has greatly helped with her sons' hunting ever since she returned. In the premiere episode of "Supernatural," Mary had to kill a Woman of Letters, though that wasn't an easy feat for her, Blasting News reported.

Dean and Sam -- especially the former -- are not too thrilled on Mary's return to the hunting world. The Winchester boys were traumatized over losing their mother in the past and naturally, they won't want to put her in harm's way again.

Ackles said that having Mary introduces a vulnerability to Dean and Sam that will be "tricky to navigate." According to the actor, Dean only had to worry about Sam prior to Mary's return, but now "he's really going to have to worry about his mother and his brother."

Next month's "Supernatural" episode titled "The One You've Been Waiting For" centers on Adolf Hitler. In the long-running series' Nov. 10 episode, Dean and Sam will prevent a group of Nazi necromancers from resurrecting the late dictator, whose soul has been trapped in a 1930's gold pocket watch, Parent Herald previously reported.

Why do you think Castiel and Lily became enemies? Share your thoughts below. "Supernatural" Season 12 returns for its third episode on Oct. 27 at The CW.