The Kennedy family drama Chappaquiddick, which revolves around the 1969 incident in which a young Ted Kennedy got in a car accident that killed a former Robert Kennedy campaign worker named Mary Jo Kopechne, has added a pair of new cast members: Jim Gaffigan and Olivia Thirlby. As The Hollywood Reporter puts it, “The script tackles what some have described as the seven most dramatic days of Kennedy’s life,” when the senator was balancing the moral and legal ramifications of how to handle the fatal crash, and how to protect his political career/family’s legacy. Gaffigan will play District Attorney Paul Markham, who was present on Chappaquiddick Island on the night of the incident, and gave a positive testimony about how Kennedy handled the accident. Thirlby will play one of the “boiler room girls,” which was a group of six single women who worked on Robert Kennedy’s 1968 presidential campaign and attended the Regatta Weekend reunion party where everyone was drinking on the night of Kopechne’s death. The two actors join a cast that includes Bruce Dern (Joe Kennedy), Kate Mara (Kopechne), Ed Helms (Joe Gargan), and Jason Clarke (Ted Kennedy). John Curran is directing.