When Blake Shelton settles into his red swivel chair on Monday (Sept. 22) for the seventh season of "The Voice," he'll be surrounded by some new faces in the show's coaching section.

Oh, sure, Shelton's buddy and long-time coach Adam Levine will be back to keep the country star company. But two new coaches - pop stars Gwen Stefani and Pharrell Williams - join the hit show.

"I'm having so much fun this year, I'm probably having as much fun this year with 'The Voice' judges as I did that first year," Shelton told CMT Hot 20 Countdown. "It's hard to explain why, but I think it's because they were so unexpected to me.

"I had no inkling what Gwen Stefani was gonna be like, at all. She's the most sweet and, I mean, if I could be that normal, I'd be better off. I love her. I mean, I really do. I like working with her. We've had a ton of fun.

"And, of course, Pharrell, I didn't know what to expect from him," Shelton continued. "First of all, those two (Stefani and Williams) are like brother and sister, anyway, comin' into the thing, they've made so many records together. But he's kinda just a shy, quiet guy. But don't confuse that. He does talk a lot. He's kind of got a soft presence about him, but you're not going to shut him up."

Even though the new cast is already starting to feel like a family, Shelton knows that even with three wins under his belt, he has his work cut out for him this season.

"When people are new on the show - and I learned this with Usher and Shakira - you're like, 'Oh, man. We're just gonna roll over these people,'" he explains. "You figure out how to play this game as far as getting artists to come over to your team. And they did unbelievable in the blind auditions.

"Pharrell has been a coach his whole life, anyway, basically finding stars and producing records and writing songs, so he's gonna do great. And people fall in love with Gwen the second they see her or hear her talk. It's gonna be a tough year."

In addition to the all-star cast of coaches, the show's contestants will get a little help from guest mentors like Taylor Swift and Little Big Town.

"The Voice" airs Monday and Tuesday nights on NBC.