Kelly Clarkson's ‘jittery' and ‘shaky' behavior worries pals

Kelly Clarkson has left her friends worried with her recent “jittery” behaviour.

According to an insider, Clarkson’s dieting is making her erratic and jittery.

"Sure, she lost the weight, but everyone's worried she's going overboard," a tipster told the Globe. "She hasn't been herself at all lately."

They added: "She's shaky on stage, she's jittery, her moods are all over the place — and she looks gaunt because her cheeks are sunken in. It's not good!"

In a video from her recent concert, the Stronger singer admitted to the crowd that she was in a "weird mood," and went on to forget the lyrics to her song Mine. She also suffered a wardrobe malfunction.

The tipster added: "She used to be on top of her game, so to hear her forget lyrics and go off on a tangent in front of her audience is distressing. She's skipping meals. She's not getting enough nutrients. She has no energy. It's like she's faking being excited!"

"Kelly's friends are doing their best to support her," the insider added. "But they miss the lively, healthier girl they used to know!"

The source also claimed that the Because Of You crooner is having a hard time dealing with her divorce from Brandon Blackstock after six years of marriage.

The source said: "It keeps her up at night. It's an emotional roller coaster she can't get off!"