Country star Carrie Underwood has joined fellow American Idol winner Kelly Clarkson as a spokesmodel for energy drink Vitaminwater.

The Before He Cheats hitmaker has secured an endorsement deal with the drinks company.

Underwood, who will appear in upcoming Vitaminwater commercials, insists it wasn’t difficult for her to sign up for the job - because it’s her favourite drink.

She says, "I have a hectic schedule, and Vitaminwater really helps to keep me going. I like to have a lot of energy on stage, and since Vitaminwater energy happens to be my favourite flavor, I’m thrilled to have my name on it."