Credit: Jamie McCarthy/; ABC/PATRICK HARBRON

Rosie Huntington-Whiteley has been hailed the sexiest woman in the world by FHM and Maxim, but the 24-year-old supermodel says she wasn't always so pretty.

"I was a bit of an Ugly Betty when I was 15," she tells the December Issue of Harper's Bazaar.

Huntington-Whiteley is of course referencing the character made famous by America Ferrera, who earned a Golden Globe for her portrayal of the frizzy-haired, four-eyed fashion magazine assistant on the ABC series Ugly Betty.

The British bombshell -- who made her film debut in 2011's Transformers: Dark of the Moon -- says she would show up at model castings "in trainers, with braids, a ton of makeup, plucked eyebrows...I had braces."

Things obviously turned around for Huntington-Whiteley, who later became the face of Burberry and the body of Victoria's Secret. As her modeling career took off, her confidence soared.

"There's always a moment [at parties] when some great song comes on and everyone's like, 'Do the runway walk, Rosie!' And you're like, 'No, no, no,' and then you begrudgingly get up and do your thing," she tells Harper's Bazaar. "It might be my little party trick. It always gets applause."