The secret to Adele's confidence? A healthy attitude ... and Spanx.

"She always wears Spanx on the red carpet. Good ­underwear is really important, it smooths you out," the singer's stylist Gaelle Paul told The Daily Mail.

"Adele is really OK with how she looks," Paul said. "I don't think she ever lacked confidence. She doesn't have that insecurity that a lot of other people I dress have."

And don't think the singer typically wears black to look slimmer. The chanteuse has other motives for her noir wardrobe! "Adele always wants to wear black because she loves Johnny Cash and he wore black," Paul revealed. "She also loves June Carter Cash because she and Johnny were so much in love and they had this wonderful marriage," he added.

Though Adele's weight has garnered her criticism from Karl Lagerfeld and Joan Rivers, the '21' songstress couldn't care less. Adele explained simply, "My life is full of drama and I won't have time to worry about something as petty as what I look like," I don't like going to the gym. I like eating fine foods and drinking nice wine."

She continued, "I've seen people where it rules their lives, who want to be thinner or have bigger boobs, and how it wears them down. And I don't want that in my life. I have insecurities, of course, but I don't hang out with anyone who points them out to me."

Amen, Adele!