NEW YORK — Valerie Harper has agreed to give a first-person account of her battle with terminal cancer to NBC News.

The network says Meredith Vieira will host the documentary, which will air in prime time. No airdate has been set.

The actress gained fame playing Rhoda Morgenstern on television's "The Mary Tyler Moore Show" and "Rhoda." She announced this year that she has been diagnosed with brain cancer. She was given as little as three months to live when diagnosed March 6, which she has already exceeded.

NBC says the 73-year-old Harper has allowed cameras to follow her since she was diagnosed.