By James Hibberd
Updated October 26, 2011 at 12:00 PM EDT

A Rescue Me veteran is stepping into The CW’s Ringer as a trouble-making step mom.

Andrea Roth has been cast in the recurring role of Catherine — that’s the ex wife of Siobhan’s husband Andrew Martin and the mother of Juliet. She’s described as “beautiful, sexy and intimidating … smart, conniving and can be very vindictive.”

Catherine comes to New York and “causes turmoil for the Martin family” (which, naturally includes our heroine SMG). In addition to appearing in 93 episodes of FX’s Rescue Me, Roth also had a recurring role on CBS’ Blue Bloods.