Army Wives actress Sally Pressman is joining Once Upon a Time season 4, but her character’s identity has yet to be revealed.

Once Upon a Time season 4 is still a bit of a blank slate, despite the heavy focus on the Frozen storyline. Who will be the main new heroes and villains introduced, and is anyone here to stay?

The latest mystery addition to the guest star roster is Sally Pressman, best known for her role as Roxy on Army Wives.

The actress announced her casting on Twitter, adding a few hints about her role:

There has been some speculation that Pressman will be playing Anna (Elizabeth Lail) and Elsa (Georgina Haig)’s mother, who (spoiler alert!) tragically drowns when she and her husband are traveling by sea.

Previously, it has been speculated that Lost actress Elizabeth Mitchell had been cast in that role, but EW has recently revealed that Mitchell will be playing a villain.

Executive producer Adam Horowitz says of Mitchell’s villainous role, “There’s a dark side that Elizabeth is accessing and she’s doing so in chilling fashion.”

Hmmm, a chilling fashion? Could that mean that Mitchell will be playing another version of Elsa’s Snow Queen, but the actual evil queen imagined in the original H.C. Andersen tale? It certainly would be a first for Once Upon a Time to pit two interpretations of the same source character against each other.

And maybe Mitchell’s Snow Queen (if that is indeed her role) is part of the explanation for how Elsa got her powers. Perhaps Mitchell and Pressman’s characters are sisters, which would make Mitchell’s Snow Queen the maternal aunt of Elsa and Anna.

Are you looking forward to seeing Sally Pressman on Once Upon a Time? Do you think her role will be related to the Frozen storyline?

Once Upon a Time season 4, episode 1, “A Tale of Two Sisters,” airs Sunday, September 28 at 8/7c on ABC.