AceShowbiz - Kelly Clarkson freaked out when she lost her voice after giving birth to her two children.

The "Stronger" singer and husband Brandon Blackstock welcomed daughter River in 2014 and son Remington two years later.

While the 36-year-old carried on working, releasing album "Piece by Piece" in 2015, Kelly has now revealed she feared her singing career might be over after she became a mum.

"How much I vomited was scary," she told Britain's Metro newspaper. "I was warned by Jennifer Nettles, a country singer, 'Don't freak out when you have kids, because (you're) not going to be able to sing, but it comes back'. I was a total jerk, 'That's not going to happen to me,' then it did and I freaked out."

Luckily the star had nothing to worry about, and her voice is now as powerful as ever.

The "American Idol" alumni showed off her impressive vocal range when she hosted Sunday night's (May 20) Billboard Music Awards, and covered everyone from Kendrick Lamar to Taylor Swift during her opening performance.

She also showed off a more serious side at the awards bash, held at the MGM Grand Garden Arena in Las Vegas, fighting back tears as she called for "a moment of action" following the latest high school shooting in her native Texas.

"There's something I'd like to say about the tragedy Friday at Santa Fe High School," she told the audience. "I'm a Texas girl and my home state has had so much heartbreak over this past year and once again y'all we are grieving for more kids that have died for just no reason at all.

"Tonight, they wanted me... to do a moment of silence, and I'm so sick of moments of silence... It's not working, like, obviously, so why don't we not do a moment of silence; why don't we do a moment of action, why don't we do a moment of change."