NEW YORK – Right now Bob Greenblatt is adding “live TV musicals” to his list of favorite things (right after brown paper packages tied up with string).

“Sound of Music Live!”, the first live musical on network television in more than 50 years and a pet project of the NBC Entertainment chairman, proved to be a worthwhile gamble on Thursday night.

The three-hour event, based on the 1959 Rodgers & Hammerstein musical and starring Carrie Underwood and Stephen Moyer, reeled in a whopping 18.5 million viewers overall and delivered a 4.6 rating with viewers younger than 50. Translated from Nielsen-speak, that means more than 5.5 million people in the advertiser-coveted 18-to-49-year-old demographic tuned in. That was enough to tie CBS’ top-rated “The Big Bang Theory” in the demo at 8 p.m. EST.

Locally, the production had a higher rating on Channel 2 than CBS’ half-hour comedy “The Big Bang Theory” on Channel 4.

The score here was 16.8 for “Music” and 14.0 for “Big Bang,” which is usually the No. 1 or No.2 rated program of the week here.

The broadcast delivered the Peacock Network its best Thursday-night performance with younger viewers since the finale of “ER” in 2009.