The 46-year-old singer joined James Corden for the Carpool Karaoke segment of his show on May 4 night's episode.
As he spoke to her, James admitted his wife had told him to ask her how she maintains her ageless "Benjamin Button" type appearance.
In response, she said it's her new relationship with Blake, who she started dating in November 2015, that she believes is responsible for her flawless look.
"What happened was, my life blew up. After that I kind of started falling in love, and then I wrote a whole record about that. So this is like, it's almost like, that's what the facelift is, I think," she laughed.