20030916_sim_h16_217.jpgEXCLUSIVE: Laura Linney’s Cathy is getting Miranda as a friend. Cynthia Nixon, who played Miranda on the hit HBO comedy series Sex and the City and in the 2 features the show spawned, is joining the cast of Linney’s upcoming Showtime dark comedy series The Big C as a recurring. The Sony/Original Film-produced show stars Linney as Cathy, a repressed suburban wife and mother who reclaims her life after a terminal cancer diagnosis. Nixon will play her friend. Other recurring guest stars on Big C’s upcoming first season are Gabourey Sidibe and Idris Elba.