Award-winning actress Elisabeth Moss (“The Handmaid’s Tale”) is set to star for director Ritesh Batra (“The Lunchbox,” “The Sense of an Ending,” “Our Souls at Night”) in his upcoming feature, “A Letter From Rosemary Kennedy.”

The little-known but haunting story of the eldest sister of President John F. Kennedy, who spent a lifetime hidden from public view because of the political ambitions of her father, Joseph Kennedy, is based on a Black List spec script by first-timer Nick Yarborough.

“A Letter From Rosemary Kennedy” is produced by Jason Michael Berman of Mandalay Pictures (“The Birth of a Nation,” “Little Evil,” “Mediterranea”), Kevin Turen of Guy Grand Productions (“Assassination Nation,” “The Birth of a Nation,” “99 Homes”), and Moss. Richard Arlook, Allard Cantor, and Jarrod Murray executive produce.

Mister Smith Entertainment will introduce the new title — which MSE’s David Garrett describes as a “a perfect alignment of a magnificent writer, a great actress and a singular film maker” — to buyers at this month’s European Film Market in Berlin.

Endeavor Content is selling North American rights.

“A Letter” turns on the first daughter of Joseph Kennedy Sr. and Rose Fitzgerald who was blessed with the Kennedy family beauty but born with learning difficulties and developmental challenges. A vibrant beautiful young woman caught smiling in photos with JFK, whom she doted on, she was, however, a large embarrassment to Joseph Kennedy Jr. who was priming his children to be great statesmen – and stateswomen. As result, she was hidden from public view and ultimately institutionalized by her father, suffering a botched lobotomy. The film is based on personal letters illustrating her wish to connect with her family and how her story became a catalyst for change and left behind a legacy for generation to follow, Mister Smith said in a statement.

“The movies about the Kennedy family are deservedly stormy affairs, but here’s a story about the storms within all of us,” said Batra.

“We are thrilled to be bringing this poignant and true story to life based on one of the hidden gems of the Kennedy family, with a masterful filmmaker in Ritesh Batra, the brilliant Elisabeth Moss, and a beautifully crafted screenplay by Nick Yarborough,” said producers Berman and Turen.

Starring in Ruben Ostlund’s Palme d’Or winning “The Square,” now nominated for an Academy Award, Moss played Peggy Olsen in “Mad Men” and has consolidated her global fame playing the protagonist of Hulu’s “The Handmaid’s Tale.”

Batra, who burst through to attention with “The Lunchbox,” his debut feature, which won a Bafta nomination for best foreign-language film, is currently editing his original India-set love story “Photograph,” which he produced alongside Neil Kopp, Anish Savjani and Michael Weber from The Match Factory, with financing from Amazon.

Moss is represented by WME, Ribisi Entertainment, and the Independent Talent Group in the U.K. Batra is represented by Casarotto Ramsay & Associates and William Morris Endeavor.