Kate's mother was portrayed by Beth Broderick.
My collection includes a
Rittenhouse LOST Archives Autograph card
Rittenhouse LOST Archives Character card #5
I also have an autographed photo of Beth Broderick
from her role as Aunt Zelda on "Sabrina The Teenage Witch".
This photo originally belonged to my sister,
so I blocked out her name in inscription.
(Her company provided hair accessories to the series.)