Singer Kelly Clarkson dropped significant weight by adapting her diet to treat an autoimmune disease and thyroid condition.

The Stronger hitmaker stunned at the 2018 CMT Music Awards on Wednesday (07Jun18) in a long black Alex Perry gown with a side slit, studded Balmain pumps, and dazzling, large square statement earrings from Saint Laurent, and many fans noticed her weight loss as she walked the red carpet.

However, Kelly reveals her new slimmer look was not achieved through traditional means, like exercise.

"I'm not working out!," she tells Extra. "I think people think I'm working out and I'm like, 'Don't think I'm going to come play some sport!'"

Instead of hitting the gym, the star transformed her diet in a bid to treat an autoimmune disorder.

"I literally read this book, and I did it for this autoimmune disease that I had and I had a thyroid issue, and now all my (hormone) levels are back up," she explains. "I'm not on medicine anymore because of this book, it's called The Plant Paradox (by Steven R. Gundry, MD). It's basically about how we cook our food, non-GMO, no pesticides, eating really organic... Literally, I haven't worked out at all!"

Kelly didn't name her autoimmune disease directly, but she has previously opened up about her "nonexistent" thyroid to Jenny McCarthy, telling the comedienne on her SiriusXM show last year (17) her medical problems with the hormone regulating gland affected her breastfeeding with her two kids.

The pop star also showed off her new slimmer look last month (May18) while hosting the Billboard Music Awards. Kelly pulled off fashion marvels at the prizegiving, changing her outfit eight times, opting for three Christian Siriano looks, a Balmain number, and a Versace leather dress, among others, with every ensemble carrying a dazzling black, gold or sparkly theme.