Guess those teeth weren’t made for brushin’.

Jessica Simpson has only a nodding acquaintance with a toothbrush, the singer told iheartradio on Thursday.

"I don’t brush my teeth," said the "Irresistible" singer, according to UsMagazine.com. "No, really!"

"I just use Listerine - and sometimes I'll use my sweater," she added with a laugh.

"I do brush every now and again, but my teeth are extremely powerful. Fine, maybe when I'm 60 I'll be all, ‘ow!’"

Right ... and she’s single because ... ?

The "These Boots Are Made for Walkin" cover artist also confessed that her nutrition habits aren’t always the best.

"Growing up in Texas for me, fish was a fish stick," she said. "We weren't really the healthiest of people. [My mom] didn't force me to eat healthy."

She also briefly touched upon John Mayer’s recent raunchy remarks about their sex life, where he compared knocking boots with the singer to snorting drugs.

"Maybe in his mind he was thinking about giving me a compliment but he wasn’t," she said.

"In relationships, in general, going through a divorce and going through very public break-ups ... you don’t want to disappoint people who are rooting for you to be successful in love. I just have to find the right man."