They join the previously reported Cory Michael Smith and Tony and Oscar winner Frances McDormand in Jane Anderson's miniseries, which is based on Elizabeth Strout's Pulitzer Prize-winning collection of short stories about a woman observing affairs, crime and tragedy in her small New England town.

Gallagher will play Christopher Kitteridge, the son of Olive and Henry (Richard Jenkins). The Tony winner's stage credits include Rabbit Hole, Spring Awakening, American Idiot and Jerusalem. Hs TV work includes "The Newsroom," "Law and Order: Special Victims Unit" and "The West Wing."

Kazan, who will play Denise, Henry's co-worker, has performed onstage in Come Back, Little Sheba; The Seagull; and A Behanding in Spokane. Her film credits include "Happythankyoumoreplease," "Revolutionary Road," "Me and Orson Welles" and "Ruby Sparks."

Plemons has apeared in "Breaking Bad," "Bent," and "Friday Night Lights." He will play Jerry McCarthy, Henry’s delivery boy at the pharmacy.

McDormand (Good People, The Country Girl, Awake and Sing!, "Fargo") will play the title role, and Smith (Breakfast at Tiffany's) will play Kevin Coulson, an ex-student of Olive's, who returns to the small town.