Katie Cassidy by Eric Charbonneau/WireImage.com
Supernatural has filled one of the two new female series-regular roles I first told you about last month.

Katie Cassidy - the 20-year-old daughter of '70s teen idol David Cassidy - has been tapped to play Ruby, a fellow demon hunter that Sam and Dean meet in the show's third-season premiere. In the casting breakdown, the character is described as "sexy, brutal and ruthless."

Cassidy's previous credits include the features Click, When a Stranger Calls, and Black Christmas and recurring roles on 7th Heaven and Sex, Love and Secrets. She has also signed on to play Lucy Ewing in the long-in-the-works Dallas pic.

No word on who'll play Bela, the "beautiful, funny and confident" mercenary who lacks a conscience, but check back in another day or so. I should have a name by then.