"It's all about the heart, and he has that big ol' gigantic heart in there, so he's quite an attractive human," Stefani tells PEOPLE exclusively
“He’s perfect for it,” the No Doubt rocker, 48, tells PEOPLE exclusively. “Somebody that is funny and has a sense of humor is sexy — that’s the No. 1 thing.”
While the country superstar constantly has everyone around him in stitches, his sexy attributes go far beyond just being able to get a laugh out of his loved ones.
“[He’s] somebody that is at the top of their game and talented and genuine and cool and generous and just not self-aware at all — completely a man,” continues Stefani, who teamed up with Shelton on her holiday duet “You Make It Feel Like Christmas” and is hosting an hour-long holiday special airing Dec. 12 on NBC.
“I guess I’ve been kissing the #sexiestmanalive all this time but @people I knew that already!” she Tweeted Wednesday morning.
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The 41-year-old star — whose new album Texoma Shore hit No. 1 this week on Billboard‘s Top Country Albums Chart — also has no idea how attractive he truly is, according to his girlfriend.
“He doesn’t even know how cute he is. [He]’s cocky but only because he’s a cowboy!” Stefani jokes.
At the end of the day, however, what makes Shelton the sexiest man in the world to Stefani is his heart.
“It’s interesting because I don’t think any of those things like beauty or sexy or whatever way you want to describe humans is necessarily a physical thing that people are attracted to,” she says. “It’s all about the heart, and he has that big ol’ gigantic heart in there, so he’s quite an attractive human. I’m not the only one that thinks it!”