The role will reunite her with Once Upon A Time's producers Liz Tigelaar and Jane Espenson, with whom she previously worked on Life Unexpected and Buffy the Vampire Slayer respectively.
Writing on her Twitter page, Caulfield said: "Yes, I will be reuniting with Jane Espenson and Liz Tigelaar on Once Upon A Time. Heading to [Vancouver] next week. Can't wait..."
Caulfield is expected to play the Blind Witch from the Hansel and Gretel story in Once Upon A Time's ninth episode, TV Line reports.
Caulfield also confirmed on her Twitter page that she will be appearing in Prime Suspect, writing: "People say I look like Maria Bello. Find out October 25th with a side by side comparison on Prime Suspect. Oh, and I play a porn star, so..."
She added that she "had a blast" filming scenes for the NBC crime drama.
As well as starring in Buffy the Vampire Slayer and Life Unexpected, Caulfield has had guest roles in shows such as Leverage and Private Practice. She has also worked on Gigantic, Bandwagon: The Series, General Hospital and Beverly Hills, 90210.
Once Upon A Time will premiere on October 23 at 8/7c while Prime Suspect continues on Thursdays at 10/9c on NBC.
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