Teen queen Hilary Duff has dismissed reports she has an eating disorder, and insists she lost weight because she exercised.

Duff never weighs herself and doesn't know how much weight she ended up losing while on tour recently.

She explains, "My best friend was on tour with me and we swam 30 laps every day.

"We always made sure we stayed at hotels with pools and on the days I didn't feel like doing it she'd be like, 'Let's go.'"

The SO YESTERDAY singer also cut out carbohydrates, such as pasta, rice and bread, while she was on the road and has continued working out regularly.

She adds, "When I finished that tour, my sister (introduced) me to pilates, and I just got obsessed with it. I do it three or four times a week when I'm not travelling."