Diana Hardcastle and Kristin Booth have signed on to Reelz’s The Kennedys: After Camelot, reprising their roles as Rose Kennedy and Ethel Kennedy, respectively, from the original The Kennedys miniseries.

The latest cast members join previously announced Katie Holmes as Jackie Kennedy Onassis, Matthew Perry as Ted Kennedy, and Alexander Siddig as Aristotle Onassis. Kristen Hager will play Ted Kennedy’s first wife Joan Kennedy. Principal photography begins today in Toronto, Canada.

Still to be filled is the role of John F. Kennedy Jr. Reelz says it’s conducted “a vigorous international search,” with final casting to be announced soon.

In addition to her role as family matriarch Rose in the original miniseries, stage actress Hardcastle has appeared in the Best Exotic Marigold Hotel movies, Good Woman and currently The Boy. Booth has appeared in movies Defendor, This Beautiful City and Foolproof, with TV credits including Signed, Sealed, Delivered and Orphan Black.

Also returning from the original mini: director Jon Cassar, who won a DGA Award for best miniseries with The Kennedys; production designer Rocco Matteo; and director of photography David Moxness, among others.

Based on biographer J. Randy Taraborrelli’s After Camelot: A Personal History of the Kennedy Family 1968 To The Present, The Kennedys: After Camelot comes from Muse Entertainment.