It will mark a reunion for McGillin and Buckley, who co-starred in the original Tony-winning production of The Mystery of Edwin Drood.
As previously reported, Buckley will play the role of Big Edie, the part originated on Broadway by Tony winner Mary Louise Wilson, with Tony nominee Rachel York as Little Edie Bouvier Beale, the role created by Tony winner Christine Ebersole.
The cast also include Gracie Beardsley as Lee; Matt Doyle as Joe/Jerry; James Harkness as Brooks Sr./Brooks Jr.; Sarah Hunt as Young Edie; Simon Jones as Major/Peale; and Dakota Quackenbush as Jacqueline.
The musical, which features music by Scott Frankel, lyrics by Michael Korie and a book by Doug Wright, will be directed by Michael Wilson. Performances are scheduled for Aug. 4-30 at the eastern Long Island venue. About her latest stage outing, Buckley recently told Playbill.com, "I'm thrilled to be working with the great director Michael Wilson and the wonderful, gifted Ms. Rachel York! So excited to be spending the summer in NYC for our rehearsals and August in Sag Harbor at the Bay Street Theater!"
Based on the 1975 documentary by Albert and David Maysles, the musical, according to press notes, "tells the story of Big Edie and Little Edie Bouvier Beale, the eccentric aunt and cousin of Jaqueline Kennedy Onassis. Set in 1941 and 1973 at the Bouvier mansion in East Hampton, this bold musical follows a mother and daughter on their hilarious and heartbreaking journey from glamorous aristocrats to notorious recluses in a crumbling house filled with memory and cats."
The production team includes Hope Clarke (choreography), Andy Einhorn (music director), Jeff Cowie (set design), Robert Wierzel (lighting design), Ilona Somogyi (costume design), Heather Urgina (props), Charles Swan (assistant director), Robert Bennett (production stage manager) and Denice Yaney (assistant stage manager). Casting is by Stewart/Whitley Casting.
"I am very excited to have a dream cast and creative team joining us for Grey Gardens at Bay Street this summer!" said Scott Schwartz, artistic director for Bay Street Theater. "The brilliant Betty Buckley and Rachel York will bring humanity, depth, and humor to Big and Little Edie Beale, women who are part of the shared heart and history of the Hamptons. They are joined by a cast of dazzling actors and award-winning designers, and we welcome them all. I am confident that under Michael Wilson’s inspired direction, this production will be a perfect finale for our 2015 season and an event not to be missed."
Grey Gardens premiered Off-Broadway at Playwrights Horizons in 2006 and subsequently transferred to Broadway, where it ran for 307 performances at the Walter Kerr Theatre. Grey Gardens earned a Tony nomination for Best Musical and garnered Tony Awards for leads Ebersole and Wilson, as well as for costume designer William Ivey Long.
Betty Buckley offered acclaimed performances in Broadway's Sunset Boulevard, Carrie, Song & Dance, The Mystery of Edwin Drood, 1776, Triumph of Love and Promises, Promises. She won a Tony Award for her performance as Grizabella in the Broadway production of Cats, and she starred on the London stage in Promises, Promises, Dear World and Sunset Boulevard, earning an Olivier Award nomination for her work in the latter. Her screen credits are numerous.
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