Five-time Tony winner McDonald will portray Mother Abbess with Benanti as Elsa Schrader and Borle as Max Dettweiler.
As previously reported, six-time Grammy Award winner Carrie Underwood is set to star as Maria with Stephen Moyer as World War I hero Capt. Georg Von Trapp. The three-hour production will be based on the original 1959 Broadway musical, which starred Mary Martin and Theodore Bikel.
The music and lyrics for The Sound of Music were written by Richard Rodgers and Oscar Hammerstein, respectively, with a book by Howard Lindsay and Russel Crouse.
The upcoming TV musical is executive-produced by Neil Meron and Craig Zadan. Beth McCarthy-Miller and Rob Ashford will serve as directors.
The presentation will be produced by Universal Television.