"Valerie's Story -- a Meredith Vieira Special" is to debut at 10 p.m. ET following the finale of the game show "Million Second Quiz."
"The documentary explores Valerie Harper's raw and emotional journey as she battles a rare incurable disease," a synopsis said. "Harper, who is 74 years old and had previously battled lung cancer, announced on March 6, 2013, 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. In an exclusive to 'Today,' Harper's latest MRI revealed that she had defied the odds and her neuro-oncologist Dr. Jeremy Rudnick said that she 'was pretty close to remission.' From the revelation that she had an incurable disease, to doctor's visits and experimental treatments, 'Valerie's Story -- a Meredith Vieira Special,' 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 are to be guests on Thursday's edition of "Today."
Harper is currently a contestant on ABC's "Dancing with the Stars."