Produced by NBC News’ Peacock Productions and hosted by Vieira, the documentary, according to press notes, "explores Valerie Harper’s raw and emotional journey as she battles a rare incurable disease."

Harper, who is 74 years old and a lung cancer survivor, announced on March 6 that she had been diagnosed with leptomeningeal carcinomatosis, a rare, terminal cancer. Given only three-to-six months to live, her diagnosis has turned a corner: Harper’s neuro-oncologist Dr. Jeremy Rudnick recently said that the "Mary Tyler Moore" and "Rhoda" star “was pretty close to remission.”

From the revelation that she had an incurable disease to doctor’s visits and experimental treatments, the documentary "takes an intimate look inside Harper’s reality as she lives life to its fullest with her husband Tony Cacciotti and their daughter Christina."

Harper and Vieira also make guest appearances on NBC's "Today" Sept. 19.

Harper, currently a contestant on "Dancing with the Stars," was last on Broadway in a Tony-nominated turn in Looped.