Private Practice alum Ann Cusack has landed a provocative guest-starring role in Castle‘s Season 8 premiere.

TVLine has learned exclusively that the actress will appear in the second half of the two-part season opener as Rita, a member of a top-secret organization who drops into Beckett’s life with a unique set of skills… and an unexpected connection to Castle.

In addition to her Private Practice arc as the wife of Addison’s mother Bizzy, Cusack’s recent TV credits include episodes of Backstrom, Masters of Sex, Scandal and Hart of Dixie.

Previously this summer, Castle added Toks Olagundoye (The Neighbors) in the series regular role of onetime Scotland Yard officer Hayley Vargas, while Sunkrish Bala (The Walking Dead) will recur as a high-strung tech analyst.

Castle opens its eighth season on Monday, Sept. 21.

VIDEO: Castle‘s Nathan Fillion Talks Season 8

Rick & Kate: ‘Things Have to Change’

https://www.youtube.com/watch?v=vP9IRjpVK74