Person of Interest

Harold Finch's fiancée, Grace Hendricks is portrayed by Michael Emerson's real life wife, Carrie Preston.

The character of Sameen Shaw was introduced on the show with the potential of becoming a regular, but it only happened because she was well received by the audience and the producers were happy with Sarah Shahi's performance.

The character of John Greer is portrayed by John Nolan, uncle of series creator/producer Jonathan Nolan.