Demi Lovato was ''miserable and hot'' on her last tour.

The 'Skyscraper' hitmaker - who sought treatment in rehab in 2010 for bulimia, self-harm and drug abuse - admits she wasn't as body confident as she wanted to be during her gigs last September, so covered herself up on stage, despite feeling uncomfortable.

She said: ''For someone who's preached about body image, to go on stage in head-to-toe clothing, that was a sign of somebody that was not totally secure with their body. I wasn't happy with my body image and part of me preaching was me trying to convince myself.

''I wanted to show you can survive an eating disorder and have the confidence to show yourself. For me to say all that, then go onstage in layers and swear - I was miserable. I was hot, but I didn't want to show my arms.''

The 23-year-old star is hopeful the cover of her new album 'Confident' - on which she poses in just a skimpy black top and pants - will reflect a more positive image.

She explained to heat magazine: ''I wanted to show off the confidence I've always had inside of me, but has also been covered with so much insecurity.''