AceShowbiz -

There's a Hilary Duff fever out there. You can see her picture here and there. And it is safe for us to say the actress has transformed from Hollywood teen queen to a much more mature and sexy star. It is not surprising then to see her graces the cover of US Weekly's first annual swimsuit issue.

To the publication, the starlet tells everything from her diet secret to her exercise routine. Duff openly reveals to US Weekly that media reports about her being fat has once drawn her to follow a strict diet and exercise routine. "It made me obsessed," she said. "I would beat myself up if I had some fat."

She, furthermore, admitted to stop having a strict diet when her older sister Haylie Duff told her she had went too far and was too skinny as her weight plummeted from 130 in 2003 to around 100 pounds in 2005. "She (Haylie), said, 'Why are you being so strict with yourself?' It was like an awakening," US Weekly quoted Duff as saying.

Pick up the latest issue of US Weekly, on newsstands this week, to read the other details of Duff, including her diet and exercise program.