• Sarah Steele attends the 'The Country House' Cast Photocall at Manhattan Theatre Club Rehearsal Studios on August 20, 2014 in New York City.

Sarah Steele attends the 'The Country House' Cast Photocall at Manhattan Theatre Club Rehearsal Studios on August 20, 2014 in New York City. (Photo : Getty Images / Robin Marchant)

The plot of the still untitled "The Good Wife" spinoff was recently revealed as about a financial scam that marred a young lawyer's reputation. Diane Lockhart (Christine Baranski) joins Lucca Quinn (Cush Jumbo) at a pre-eminent law company in Chicago after being forced out of Lockhart & Lee.

Like Us on Facebook

The story will pick up a year following the events of the mother series' final episode. "The Homeless Billionaire" star Sarah Steele, who plays the outspoken and smart Marissa Gold in the CBS drama series, has signed on the digital edition, according to The Hollywood Reporter. Her character is the daughter of Peter Florrick's (Christopher Noth) campaign manager, Eli Gold (Alan Cumming).

Debuted in Season 2, Steele's character appeared in 22 episodes and eventually became an important person in the life of Alicia Florrick (Julianna Marguiles). With her knack for investigation, Marissa will continue the plot of strong women investigators as she becomes Lockhart's secretary-turned-investigator.

"We're absolutely thrilled that Sarah will be joining the show," showrunners of CBS' upcoming series, Robert King and Michelle King told Deadline. "She's a magnificent comedian with the dramatic skill to keep every scene real."

It took quite a while to finalize Steele's casting as she co-stars in the Broadway hit, Tony-award winning for best play, "The Humans." The stage show was set to end on July 24 but moved to another theater on Aug. 9, and will conclude on Jan. 15. Steele also appeared in "Gossip Girl" and "Nurse Jackie."

Steele is the first to come on board after the announcement of "The Good Wife" spinoff in May during CBS' upfront presentation. The series' premiere will be in Feb. 2017 on CBS before moving to All Access. The Kings penned the premiere episode with Phil Alden Robinson, who likewise directed some episodes of the mother show's final season.

The Kings and Robinson executive produce the spinoff series with David Zucker, Brooke Kennedy, Ridley Scott and Liz Glotzer. The upcoming show is from CBS Television Studios in association with King Size Productions and Scott Free Productions. Its first season will have 10 episodes.

Watch a peek of CBS' "The Good Wife" finale in the following clip: