The former Grey's Anatomy actress will act alongside Gabriel Macht (Harvey Specter), Rick Hoffman (Louis Litt) and Sarah Rafferty (Donna Paulsen).
The announcement comes just one day after it was revealed the series was renewed for an eighth season without Patrick J. Adams and Meghan Markle.
Both their characters, Mike Ross and Rachel Zane, will leave the show at the end of season seven.
This story originally appeared on WHO.com.au