Oscar and Golden Globe nominated actress Emily Watson (Hilary And Jackie) has been cast opposite Kelli Garner and Susan Sarandon in Marilyn, Lifetime’s upcoming four-hour miniseries about tragic Hollywood icon Marilyn Monroe, to premiere in 2015.

Based on best-selling book The Secret Life Of Marilyn Monroe by J. Randy Taraborrelli, the mini will center on Marilyn (Garner), who walks red carpets in shimmering gowns while fighting a battle against demons she’s inherited from her mentally ill mother Gladys (Sarandon), whom she loves, hates and wants desperately to save. Marilyn becomes the Face and Voice of an era, yet wants most of all to be someone’s mother and someone’s little girl. Watson will play Grace McKee, the high-spirited, loving guardian to young Norma Jeane Mortenson who instilled in the lonely girl the dream of becoming a star, despite Gladys’ objections.

Marilyn was penned by The Kennedys writer Stephen Kronish. Laurie Collyer is set to direct. Asylum Entertainment is producing. Jonathan Koch, Steven Michaels, Keri Selig and Kronish executive produce.