Perhaps the only thing more intimidating than singing one of the coaches' songs onThe Voice, is singing one of their wife's songs!

That's exactly what Bella DeNapoli did during Monday's Top 20 live performances, wowing all four of the coaches -- including Blake Shelton -- with her cover of Gwen Stefani's 2006 hit, "The Sweet Escape.

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"I'm dying for Gwen to hear this," Blake raved after the jazzy interpretation of his wife's track. "There's taking a song a making it your own and then there's-- She and Akon are probably gonna have to add you to the copyright."

"That means so much!" Bella said, thanking the country star for his feedback.

Her coach, Ariana Grande -- who surprised Gwen at the final show of her Las Vegas residency over the weekend -- was also impressed by the performance.

"You have such a clear sense of artistry and such a poignant sense of self and clear point of view, " she marveled. "You're just the perfect pop star."

ET caught up with the Voice coaches at their preseason press conference, where John, Kelly and Blake placed the target squarely on Ariana's back as the first-time coach this season -- especially because so many of the show's young singers idolize the two-time GRAMMY winner's vocal talent and chart success.

"There's no disadvantage when you're Ariana Grande," Kelly agreed.

"She can't say it. I will."

"It's embarrassing to follow her [onto the Voice stage]," Blake joked of the audience's enthusiasm for the "7 Rings" singer. "It exposes my lack of celebrity."

As a longtime "huge fan of The Voice," Ariana was humble about her possible advantages, but said she couldn't wait for fans to see how her season 21 team comes together.

"I have watched many seasons and I love watching the show," she said.

 "It always has the best energy. It's such wholesome, inspiring television, and I love seeing the different voices and watching so many people start careers for themselves. It's a beautiful, amazing thing."