The actress first appeared on the CBS drama in season two in a multi-episode arc.

Sarah Shahi is joining Person of Interest full-time.

When season three kicks off this fall, Shahi will be a full-fledged series regular opposite Jim Caviezel and Michael Emerson, CBS president Nina Tassler announced on a conference call with reporters Wednesday morning.

The former Fairly Legal star first appeared on the CBS drama in February as the mysterious operative Samantha Shaw, who tracks and eliminates terrorists before they act. She has appeared in four episodes in season two.

In an interview with The Hollywood Reporter previewing her role, Shahi admitted that the character was a role she "hadn't played before." And when asked about a possible return to the show following her arc, the actress was noticeably coy: "All I've been told is that it's a multi-episode arc, and they can use me as much as they would like to through the end of their year."

CBS announced Wednesday that Person of Interest, which has anchored the 9 p.m. Thursday slot for two seasons will move to 10 p.m. Tuesdays -- taking over a time period previously held by Vegas and Golden Boy. (Both of those dramas were axed after one season.)

E-mail: Philiana.Ng@thr.com

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