Kelly Clarkson has never been "Stronger."
The 30-year-old pop singer is this summer's favorite magazine cover girl, sporting a new sleek, toned figure after reportedly dropping 30 pounds. But weight, something Clarkson has struggled with for years, remains a touchy subject for the pop star.
"I don't like talking about it so much because I think people put so much emphasis on it and lose the fact that what I do is music," Clarkson told "Nightline." "I sound the same regardless if I'm 20 pounds heavier or 20 pounds light, and I think that's the key thing with my fans and why they continue to be loyal because I'm that type of person."
Watch ABC News' Gloria Riviera's interview with Kelly Clarkson about her new show "Duets" on "Nightline" tonight at 11:35 p.m. ET.
Clarkson's motivation for slimming down, she said, came after her boyfriend "kept complaining" about his trainer's tough workouts so she decided to give it a try - the singer is dating 35-year-old talent manager Brandon Blackstock, the son of her manager, Narvel Blackstock, and the stepson of country legend Reba McIntire.
"I went because I wanted to, that was my thing," Clarkson said. "And she killed me."
The two-time Grammy winner is still reveling in the smashing success of her most recent empowerment single, "Stronger (What Doesn't Kill You)," and is a mentor on ABC's new competitive singing show, "Duets." But since being crowned the first "American Idol" winner 10 years ago, Clarkson's fluctuating weight has continued to be a topic of tabloid conversation.
"Everybody talks about weight, whether I'm skinny or bigger, they always talk about it," she said. "I'm already up on a pedestal. People already look at everything I do."
And Clarkson is not the only "Idol" contestant to publicly battle the waistline bulge during the show's reign. Last year's runner-up Lauren Alaina, 16, reportedly shed 25 pounds in her five months on the show. Breakout "Idol" stars Jennifer Hudson and Jordin Sparks have also had stunning weight-loss transformations.
In an April interview with "Nightline," country sensation Carrie Underwood, whose career was also launched on "Idol," opened up about her struggles with keeping a trim figure. While on "Idol," Underwood said she was "gently" told that she needed to lose weight.
"I was heavier than I ever had been," the 29-year-old singer said. "But they lock you in a room all day. You're waiting around for your rehearsals, you can't go anywhere, you can't do anything, you're waiting because you don't know when you're going to be up, and there's food there."
After "Idol," Underwood became a vegan and said she "immediately slimmed down" after giving up meat. She also brings her personal trainer on tour with her.
"When I'm on the road, [exercise] is part of my daily life," Underwood said. "I do my own hair and make-up on tour, so I feel like I … deserve to have someone motivating me, helping me be the best that I can be physically so I can get through the rigorous tour."