Kelly Clarkson's Weight Loss Still Touchy Subject

Singer Kelly Clarkson performs in January 9, 2012, left, and is seen again with a slimmer figure at the ABC Upfronts on May 15, 2012. Credit: Ethan Miller/Getty Images | Charles Sykes/AP Photo

Kelly Clarkson has never been Stronger.

The 30-year-old pop singer is this summers 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 dont 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 Im 20 pounds heavier or 20 pounds light, and I think thats the key thing with my fans and why they continue to be loyal because Im that type of person.

Watch ABC News Gloria Rivieras interview with Kelly Clarkson about her new show Duets on Nightline tonight at 11:35 p.m. ET.

Clarksons motivation for slimming down, she said, came after her boyfriend kept complaining about his trainers 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.

PHOTOS: Ups and Downs of Celebrity Weight Loss

The two-time Grammy winner is still reveling in the smashing success of her most recent empowerment single, Stronger (What Doesnt Kill! You), a nd is a mentor on ABCs new competitive singing show, Duets. But since being crowned the first American Idol winner 10 years ago, Clarksons fluctuating weight has continued to be a topic of tabloid conversation.

Everybody talks about weight, whether Im skinny or bigger, they always talk about it, she said. Im 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 shows reign. Last years 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. Youre waiting around for your rehearsals, you cant go anywhere, you cant do anything, youre waiting because you dont know when youre going to be up, and theres 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 Im 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.