Yet success couldn't be harder to assess in the high stakes prime-time TV gamble for NBC as the struggling network looks for its first scripted series hit since 2006.

"You can't pin a network's fate on any one show. But having said that, if you ever could, it would be this network and this show," said James Hibberd, senior staff writer at Entertainment Weekly.

"Smash", which makes its debut on Monday, is a backstage tale of writers, directors, producers and aspiring actresses working to create a new Broadway musical based on the life of Monroe.

The idea came from Spielberg, and the show is being written by playwright Theresa Rebeck ("Seminar"). It features both cover versions of hit songs and original material written by "Hairspray" Tony winners Marc Shaiman and Scott Wittman.

TV viewers have seen nothing quite like "Smash" in recent years. Show-stopping musical numbers are interspersed with darker casting couch moments and theatrical back-stabbing, giving industry watchers little to compare it with.

"It's the type of show that could either be a huge hit, or just go down in flames. It's a little bit different," said Brad Adgate, senior vice president of research at advertising firm Horizon Media.

"GLEE" FOR KIDS. "SMASH" FOR ADULTS

While "Glee" -- the quirky musical comedy about singing high school kids that gave Fox a surprise worldwide hit three years ago -- opened the door for more TV musicals, "Smash" is a drama, set in an adult world.

"'Glee' caught lightning in a bottle and was so smart to target the 'American Idol' and 'High School Musical' audience by setting it in a high school. Putting 'Smash' in a more grown-up landscape asks whether you can deliver on this genre in an older setting," said Hibberd.

Spielberg, who producers say has been very closely involved in the script and editing, believes there is enough tension in the creative process to make "Smash" interesting to all-comers.

"I think audiences will be able to relate to (it) whether or not they ever had seen a Broadway show because this is really about the drama of the characters," the Oscar-winning director told TV reporters in a January video message.

NBC, which has been mired for years at the bottom of the four biggest U.S. networks, is leaving nothing to chance.

The "Smash" pilot was screened in 10 major cities and on American Airlines flights in January. The network has been streaming the first episode on its website and on Hulu, and made it available to download on iTunes, PlayStation and other platforms three weeks before Monday's official premiere.

The network is desperately in need of a hit after what entertainment chief Robert Greenblatt admitted last month was "a really bad fall". Pricey new dramas "The Playboy Club," "Prime Suspect" and comedy "Free Agents" were swiftly cancelled, and audiences in the 18-49 demographic prized by advertisers fell 11 percent.

"'Smash' is going to be very important to us, but I don't believe it is a make or break show," Greenblatt told TV reporters in January. If it doesn't work, "it's not like we are going to go into receivership."

Adgate said a hit for "Smash" would be "a nice stepping stone" for NBC, which will be lucky to have a show in the Top 20 once football ends its season with this weekend's Super Bowl.

"Some of their hit shows are starting to fray at the edges. 'The Office' is down a bit, 'Law & Order' and 'The Biggest Loser' have all been down this year," he said.

"They really have to bolster their programming with at least some shows that can build appointment viewing, and be used as a platform to promote their line-up. I think 'Smash' is a show along with singing talent show 'The Voice' that NBC is really counting on to turn the ship around this quarter," Adgate said.

(Reporting By Jill Serjeant; Editing by Bob Tourtellotte)

• A Permanent Economic Emergency