'Sound of Music' live starring Carrie Underwood sings with 18.5M viewers

This photo provided by NBC shows, Carrie Underwood as Maria with, from left, Peyton Ella as Gretl, Joe West as Kurt, Ella Watts-Gorman as Louisa, Sophia Ann Caruso as Brigatta, Ariane Rinehart as Liesl, Michael Nigro as Friedrich, in "The Sound of Music Live!" airing Thursday, December 5, 2013. (AP Photo/NBC, Will Hart)

NEW YORK -- "The Sound of Music" has the sound of a hit for NBC.

The Nielsen ratings company says nearly 18.5 million viewers tuned to Thursday night's live telecast of the Rodgers and Hammerstein musical.

Although a preliminary audience average, NBC says the figure is expected to hold up as a measure of the three-hour production's viewership.

"The Sound of Music Live!" starred Carrie Underwood in the role of Maria. Stephen Moyer, of HBO's "True Blood", played Capt. Von Trapp.

It was the first full-scale musical staged live for television in more than a half-century.