Lifetime has inked Dermot Mulroney and Emily Watson to star in the telepic “The Memory Keeper’s Daughter.”

Longform, which is set for a March 2008 bow, is based on the bestselling Kim Edwards novel, named “book of the year” by USA Today in 2006. Mick Jackson (“Tuesdays With Morrie”) is on board to direct.

In the 1964-set movie, Mulroney plays a doctor who delivers his own twin babies — one with Down’s syndrome. In order to spare his wife heartache, he tells her the child with Down’s died at birth. The doctor tells his nurse, played by Watson, to put the girl in an institution; but instead she raises the baby as her own. Jaffe/Braunstein Films is producing “The Memory Keeper’s Daughter,” with Howard Braunstein and Michael Jaffe as exec producers. John Pielmeier wrote the script, adapted from Edwards’ book.

Mulroney’s recent credits include “Zodiac” and “Georgia Rule.”He’ll next appear in “Flash of Genius” opposite Greg Kinnear.

Watsonwill next appear with Julia Roberts in “Fireflies in the Garden,” and with Philip Seymour Hoffman in “Synecdoche.”