Actress Emma Stone will reportedly portray Rosemary Kennedy, the eldest sister of President John F. Kennedy, in a new film titled Letters From Rosemary. Rosemary Kennedy, the daughter of Joseph Kennedy, Sr. and Rose Fitzgerald, showed signs of mental disability that the family famously kept hidden. When she was 23, she was also one of the first people to receive a prefrontal lobotomies, but its failure left her permanently incapacitated.