When Paul Telegdy moved to Los Angeles, he was struck by the contrast between U.S. celebrities and those from his native Britain.

"People here took themselves extremely seriously once they were in the public eye," Telegdy, NBC Entertainment president of alternative and late night programming, said in a recent interview. Telegdy, who then was an executive with theBBC, arrived in L.A. in 2004 to start a production firm to make"Dancing With the Stars" for ABC. Initially, celebrities they approached wouldn't even return their calls.

"It was like, 'Guys, just come and play,'" Telegdy said.

Telegdy wanted to bring that playful sensibility to the singing competition "The Voice,"NBC's only solid hit last year. The beleaguered network rolls out the second season of the series (which features celebrity coaches Christina Aguilera, Cee Lo Green, Blake Shelton and Adam Levine) Sunday in the coveted post-Super Bowl time slot.

NBC desperately needs "The Voice" to hit the high notes it achieved last summer when it averaged nearly 14 million viewers an episode. The show was television's top-rated new series last season among the advertiser-friendly category of viewers ages 18 to 49. Based on a Dutch television sensation, "The Voice" was NBC's best launch of a new series since"Heroes"in 2006.

"We were going to get hung out to dry if we just did another singing show, so we said, 'Boy, let's make it sing and sound a different way,'" Telegdy said.

Several elements — including placing the celebrity coaches in big red chairs with their backs to the contestants when they first come out, and then having the coaches scrap among themselves to win over the best singers to their team — gave the show a different flair. The spinning red chairs and the selection of Aguilera, Levine, Shelton and Green, were key, Telegdy said, adding, "Casting 'The Voice' from a celebrity coach point of view was probably the most important casting that I've ever had to do."

The celebrity coaches had to come across as authentic. The four possessed legitimate credibility in the music world and had great chemistry together.

"It might just be the way the show was set up, but these judges feel more accessible to viewers," said Amy Sotiridy, director of national broadcast for the ad-buying agency Initiative. Her firm represents car company Kia, which is a show sponsor.

"The audience also likes the pop culture and gossipy element," Sotiridy said. "These people are in the tabloids all the time, and people are wondering: Is Christina really nice or not? Does she really get along with Adam or not?"

But the main selling point was the show's positive energy.

"The [judges] are telling people how to get better, and because they are stars in their own right, their advice is more valuable," Sotiridy said. "They are not just saying, 'You stink, now get out of here.' "

David Scardino, entertainment specialist with RPA, a Santa Monica ad agency, added, "There is a fair amount of mentoring, and that can be pleasing for viewers."

That's precisely what makes the show work, NBC's Telegdy said.

"People love success, and the idea that there are people who want to help you succeed," he said. "There is something nuanced in 'The Voice' that feels very generous on the behalf of those judges. If you see someone who needs help, you help them. You may feel better for it."

meg.james@latimes.com