Irish American actress Megan has vowed to cause 'physical harm' to the photographer who leaked a photo of her topless on the web.

The 'Transformers: Revenge Of The Fallen' actress said that a photographer secretly took pictures of her topless on a camera phone as she filmed her latest role as a circus sideshow performer in new flick, 'Passion Play.'

Speaking to Allure magazine, Fox warned: 'If I knew who took this picture, I would personally cause them harm – physical harm.'

The 24-year old star, who was recently voted FHM's second sexiest woman in the world behind Girls Aloud star Cheryl Cole also added that her body is for selected audiences only and not for secretive camera men who want to exploit her fame.

Fox fumed: 'I’m not a f***ing reality TV star that’s courting the paparazzi and wants my f***ing picture taken all the time.'

She added: 'I’m at my job and I’m trying to play a character and I’m trying to be serious, and this is the s*** that’s happening to me. It makes me furious.'

Megan Fox in "Transformers"