Several former cast members are scheduled to return to the show, or have been asked back. Elizabeth Mitchell returns as fertility specialist Dr. Juliet Burke. Mitchell has stated that her return is "instrumental to the story". Dominic Monaghan returned as rock star Charlie Pace in four episodes. Jeremy Davies returned as physicist Daniel Faraday in multiple episodes. Ian Somerhalder also returned as Flight 815 crash survivor Boone Carlyle in several episodes. Rebecca Mader, who portrays anthropologist Charlotte Lewis, also returned. The producers have also confirmed that Harold Perrineau and Cynthia Watros, who portray Michael Dawson and Libby Smith, respectively, returned in the second half of the season. About the return of Libby, Cuse stated, "Finally, all of your questions [about Libby] will be answered", however, Lindelof jokingly responded, "No, they will not". Michelle Rodriguez, another second season star, returned as police officer Ana Lucia Cortez, following a brief cameo in the fifth season. Maggie Grace, who portrays Shannon Rutherford, Boone's stepsister, was asked to return at the beginning of the season, but Grace was unable due to her schedule; she appeared later in the season, instead. Furthermore, the producers wished to bring back the character of Walt Lloyd, however Malcolm David Kelley, who portrays Walt, has aged significantly and the producers are working to overcome this obstacle.