Her apparent disappearance during their childhood is potentially behind Luke Spencer's (Anthony Geary) unsettling mental breakdown these days on General Hospital, but fans are soon going to actually meet the mysterious Patricia Spencer and may finally find out how she plays into the current drama.

Dee Wallace (Grimm, The Whispers), has been cast to join the ABC soap opera as the long-lost older sister of Luke and Bobbie (Jacklyn Zeman), according to Soap Opera Network. And while it is unclear when exactly she will possibly show up in Port Charles, her appearance could finally provide the answers both Luke's loved ones and fans have been clamoring for for a long time.

Luke has been acting strangely for more than a year on the soap, and has become increasingly more dangerous as time has gone on-recently orchestrating an attempt to blow up the Haunted Star with nearly everyone in Port Charles-including his wife and daughter-on board. Many believed he had been an impostor who was faking being Luke for a long time, with the real Luke Spencer locked away in a mental institution.

However, it was revealed after the near-bombing that it had been Luke all along-and he was acting upon two very different split personalities, with the switch bringing him back to his evil one after brief returns to his good side being activated by any mention of his childhood, and specifically, Patricia, who didn't move to Florida with Luke and Bobbie.

Regardless of what answers her character will bring, Wallace is thrilled to be a part of the cast, and has admitted that taking on the role was actually challenging.

"I have never had a greater challenge, never had more fun and never felt so much a part of a family on a set," she said. "You do more in one day on daytime than you do in a week on an episodic. I couldn't have more respect for colleagues than I do now."

General Hospital airs Monday-Friday at 3 p.m. on ABC.

Tags: general hospital ABC Soap Operas