Gwen Stefani Gwen Stefani

Thanks to her unique voice and trend-setting style, Gwen Stefani has never had a problem standing out. But on one of her first days on the set of The Voice, the lead singer of No Doubt quickly realizes she is going to have to do something big to set herself apart during the blind auditions.

All four coaches have pushed their buttons and are on their feet to give a standing ovation to the impressive male singer in front of them. Series vet and two-time winner Adam Levine ups the ante by climbing onto his iconic red chair and placing his feet on the armrests to stand above his competition. Stefani does one better: She takes off her white high heels to climb her chair and stand on the video screen behind her  to rise above Levine. Suffice it to say, the competition is going to be tough on this season of The Voice, premiering Monday at 8/7c on NBC.

Stefani, along with "Happy" singer and mega-producer Pharrell Williams, signed on for the NBC hit last spring several months after original coach CeeLo Green announced his permanent exit from the show and news broke that Christina Aguilera was pregnant. "I was afraid, and I had a reason to be," Stefani told reporters. "I was really nervous about just coming on the show and doing something so different, and I didn't know what it was going to be."

Although she's been the lone female in No Doubt for 25 years, she admits being the only lady on The Voice made her think twice. "It's one thing to be in the boys' club with guys you have known since you're 16 years old, but to walk onto this platform with these guys that have been doing it already and not knowing them, I was freaked out a little bit," she said.

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However, Stefani didn't have much time to mull her offer, which came shortly after she had given birth to her third child. "It was so quick and spontaneous, and I think that's what's been the best part about it," Stefani said. "I didn't know that I was going to be sitting inside of a black and red spaceship for the next three months."

This isn't the first time that The Voice has to find new blood. Usher and Shakira have both judged the last two spring cycles when Aguilera and Green left to pursue other projects. But it still remains to be seen whether viewers will take to Stefani and Williams as well as they have the other coaches. "You just never know what the chemistry is going to be like when people come in," Levine said. "These guys came in, and... nstantaneously we all just kind of congealed. ... The chemistry was so quick with all of us."

It helps that Stefani has some history with the reality competition's other new coach. She and Williams worked together on No Doubt's 2002 hit "Hella Good" and also on Stefani's 2005 hit solo effort "Hollaback Girl." In Stefani's first TV appearance this year, the two performed the song on The Voice after she signed on. "Being around someone like Pharrell is like a gift," Stefani said. "He just has such a big heart. He gives away so much of himself. He's perfect for the show, and he's perfect for these kids because he's very  nurturing, and he's very, very generous with himself, and I just like being around that energy."

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However, there was another partnership on The Voice that gave Stefani serious pause — bringing on her husband, Bush singer Gavin Rossdale, as her team's mentor. "I went back and forth about having Gavin on because we have only collaborated on babies before," she said. "We got in a little fight about it the night before because I was like, 'I don't know if I can handle this. It's just too much.' Then I slept on it, and in the morning I said, 'You know what, let's do this. It's going to spice things up.' And it was awesome."

If anything, it sounds like working together may have brought the two closer together, and reminded Stefani why she signed up for The Voice in the first place. "I have never been in this position to be a coach, and for both of us to look back at everything we've done in our careers and to sit there together and be on the same page  ... I'm getting so much out of it," she said. "Now I get it why this happened to me at this time in my life why I'm doing this. It's so inspiring and rewarding."

The Voice airs Mondays and Tuesdays at 8/7c on NBC. How do you think Stefani will do as a coach?

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