StarTraks 1 / 15

Kelly Clarkson has been undergoing some serious makeovers as of late, and at Thursday night's "Duets" taping, Us Weekly got her to open up about her 30-pound slim down.

"There's no secret!" the 30-year-old expressed to Us at the event held at the CBS studio in Studio, City, Calif. "It's just trying to eat a little better and work out a little more. But no matter what size I am, I love performing, no matter how big or little I am! I feel good."

PHOTOS: American Idol stars' weight ups and downs

According to an insider, the 5-foot-4 star decided to slim down for good after watching a recording of her December performance on VH1 "Divas Celebrates Soul." "She saw how heavy she was and she didn't like it. That's when she decided to really get into shape," the source told Us.

PHOTOS: Us Weekly's hot bodies winners!

But dropping several dress sizes isn't the only transformation the "Stronger (What Doesn't Kill You)" singer is excited to show off. On June 6, she traded her glossy brunette locks for a blond hair color.

"I love it!" she told Us about her summer hair switch up. "People keep asking me if I am having more fun, being blond, but I always have fun whether I'm blond, redhead or brunette! I always have fun, dammit!"

The two-time Grammy winner hasn't been having fun all by her lonesome, however -- since late last year, she's been spending time with her boyfriend, 35-year-old Nashville, Tenn.,-based talent manager Brandon Blackstock (Reba McEntire's stepson and the son of her manager, Narvel Blackstock).

PHOTOS: Love lives of 'American Idol' stars

"I'm too happy! He's ruining my creativity!" Clarkson, who is famous for her brokenhearted power ballads, joked to Us last month. "I'm writing all this happy s--- It's killing me."

This article originally appeared on Kelly Clarkson Talks Weight Loss, Being a Blonde


Kelly Clarkson: New Relationship Inspired Weight Loss

Teri Hatcher Debuts Short Hair

Kelly Clarkson: I've Finally Found Someone