TV Line reports that the actress will play a real estate broker who becomes caught up in a murder investigation.
Vassey played lab tech Wendy Simms on CSI from 2005 to 2010, but was axed from the CBS series prior to its eleventh season.
She recently featured in a recurring role on Two and a Half Men and has also appeared in episodes of True Calling, Dawson's Creek and ER.
Castle airs on Mondays at 10/9c on ABC. Vassey's appearance is expected to air in the spring.
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