"Living Proof" is the real-life story about a UCLA doctor's quest to develop the breast cancer drug Herceptin 2.
Lifetime said the movie is scheduled to air in October as the programming centerpiece of the network's public awareness campaign, "Stop Breast Cancer For Life."
The film is to be shot in Connick's hometown of New Orleans.
This project marks Zellweger's first television venture, as well as a reunion with Connick, with whom she recently completed filming the feature, "Chilled in Miami."
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