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Critics weren't so kind, but NBC's three-hour live broadcast of TheSound of Music was a ratings hit.

Early Nielsen figures show 18.5 million viewers tuned in, the network's biggest Thursday audience (excluding football) since the night of Frasier's series finale in 2004.

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And even among young-adult viewers, it was the network's biggest Thursday since ER's 2009 finale, and tied CBS' top-rated TheBig Bang Theoryas the night's top program.

Music, adapted from the darker Broadway musical rather than the popular 1965 film that starred Julie Andrews and Christopher Plummer, featured Carrie Underwood as Maria andTrue Blood's Stephen Moyer as Captain von Trapp. It originated from a studio on Long Island, N.Y.

NBC executives – and the rest of the TV industry – were unsure about prospects for the project, which is estimated to have cost well over $10 million. It marked the first time in more than 50 years that a Broadway musical adapted for TV aired live, though earlier shows such as Playhouse 90were TV fixtures. And like other live programming, it proved a social-media magnet.

Underwood may have proved her singing chops as an American Idolwinner and country star, but critics – and Twitter users – derided her acting skills. Still, her home state of Oklahoma proved the show's most loyal fan base: 28% of TV viewers in Oklahoma City tuned in, making it the top-rated of 56 cities measured in Nielsen's overnight ratings.