The celebrated actors will be part of the Master Voices production of Dido and Aeneas, which will be presented April 28 at 7 PM and April 29 at 8 PM.
The evening will feature Henry Purcell and Nahum Tate's Dido as well as an untitled world premiere by Michael John LaChiusa. Tony winner Ted Sperling will conduct the Orchestra of St. Luke's.
O'Hara is currently back on Broadway in the Lincoln Center Theater revival of The King and I; Clark was recently seen in the Broadway revival of Gigi.
The 2015-16 Master Voices (formerly the Collegiate Chorale) season will also include The Pirates of Penzance; or, The Slave of Duty (Oct. 15-16 at City Center), The Life and Death(s) of Alan Turing (Oct. 17 at Merkin Concert Hall), Mahler's Symphony No. 2 (Nov. 5 at Carnegie Hall), Mahler's Symphony No. 2 (May 29, 2016, at Carnegie Hall) and a world premiere-work composed by Marisa Michelson (June 2016).
For tickets and more information visit www.mastervoices.org.