The musical couple shared a photo of them kissing under some strategically-placed mistletoe on the No Doubt artist's Instagram story Christmas Eve.
The Voice coach looks casual in jeans and a black sweater in the snap, while Stefani rocks a black top, festive skirt and high bun.
The rocker also got kisses from her three sons, whom she shares with ex Gavin Rossdale, 11-year-old Kingston, 9-year-old Zuma and 3-year-old Apollo.
In a precious Christmas moment, Stefani quizzes her youngest on what the mistletoe tradition actually is.
"Do you know what this is?" she asks her son about the mistletoe, who responded, "It's a kisser?"
"Somebody that is funny and has a sense of humor is sexy — that's the No. 1 thing," she said. "[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."
Stefani noted that despite his talents, the sexiest thing about Shelton 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 explained. "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!"
She added that Shelton doesn't even know how good-looking he really is.
"He doesn't even know how cute he is," she said. "[He]'s cocky but only because he's a cowboy!"Photo credit: Shutterstock.com