The Voice's Blake Shelton on Season 4 Success: "The One Thing You Can't Fake Is Chemistry"

Adam Levine insists he wasn't nervous about adding two new coaches — Shakira and Usher — into the mix for Season 4 of The Voice. However, his fellow judge Blake Shelton says he wasn't so sure.

"I was nervous because we knew how well the show was doing. It was beating the odds. We knew we had something that worked," Shelton told reporters at NBC's Summer Press Day on Monday. "The one thing you can't fake is chemistry and I'll be damned if it's not as strong as it's ever been."

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Indeed, The Voice has actually improved its already stellar ratings performance despite the absence of Cee Lo Green's assorted animal mascots and Christina Aguilera's colorful critiques. The Season 4 premiere improved 14 percent from the show's fall start for Season 3. "It's obvious when you watch the show that we have a lot of chemistry," Levine said. "It's a very different chemistry than the chemistry before, but we're happy it's there."

Shakira said it was fairly easy to jump on board, despite her admitted lack of preparation before shooting began. "Something that is very distinctive about this show is how real it is. There's nothing fake about it," she said. "I was thrown to the lions with no rehearsal time. And there was really no guidance whatsoever. The producers only told me, 'Shakira, be yourself.' There are no poses here."

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The Latin singer says it's this authenticity that made The Voice a must-watch, even for her. "I usually hate to watch myself on TV. I don't enjoy listening to my own music or watching my own music videos, but I do enjoy, on Mondays and Tuesdays, actually watching the show because it's so entertaining."

While it was an easy move into the big red chairs for Shakira, Usher revealed he got one major critique from NBC executives when taping first started — about his now-signature one-leg-up pose. "At first, the network was against that because they felt it wouldn't read well," he said. Thankfully, those reservations were short-lived. "This could be something that we obsess over or overthink, but they make it such a fun environment," Usher added.

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The new judges have not only breathed a new energy, and some new moves, into the singing competition, but the coaches said it's also opened their eyes to new music. Shelton said that his wife, Miranda Lambert, sat him down and spent more than three hours playing him  songs and music videos from Shakira and Usher's respective catalogs. "I'm so sorry," Shakira jokingly lamented. "I saw your videos. Why would you say you're sorry? I didn't have to watch HBO or Showtime," Shelton joked about Shakira's sometimes revealing videos.

Shakira, in turn, said that The Voice has helped her learn to love country music. "Shakira asked me who you are," Levine jokingly told Shelton during the panel.

"Well, Usher asked me why you're such an a--hole!" Shelton retorted.  

Yes, it seems the chemistry between The Voice coaches is very much alive and well.

The Voice airs Mondays and Tuesdays at 8/7c on NBC.