When Gwen Stefani sat down to chat with Ellen DeGeneres Friday (Dec. 8), the famously goofy talk-show host couldn't resist poking a little fun at the singer's  boyfriend, Blake Shelton, who was famously crowned People's Sexiest Man Alive this year.

"I was watching The Voice and this is really just getting to his head," DeGeneres deadpanned, before screening a video of Shelton and Stefani's Monday (Dec. 4) duet on the reality show performing her hit "You Make it Feel Like Christmas."

DeGeneres had her peeps do a little clever digitizing on the video, so Shelton appeared to be dancing in his skivvies. Precisely, a pair of tighty whiteys with "BLAKE" emblazoned on the rear. Adding to the fun, the clip included perfectly placed shots of fellow Voice coaches Adam Levine and Jennifer Hudson looking perturbed...and downright disturbed.

Stefani, for her part, gamely cracked up at the (admittedly funny) goofiness, and joked "Yes, it's tough to be around him," before reiterating that she finds Shelton attractive for his personality, "big ol' heart," and sense of humor.

"He doesn't even take himself seriously," she noted. "He's such an incredible person."

"You Make It Feel Like Christmas" is the title song of Stefani's new Christmas album, which was released Oct. 6. While the duet between the much-publicized lovebirds was unquestionably the promotional highlight of the set, the album also features other new songs sung by Stefani, as well as holiday classics including "Jingle Bells," "Let It Snow," "Silent Night" and "Santa Baby."

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