Katy Perry has said that she is terrified of falling asleep while travelling in cars. The 'Waking Up In Vegas' singer revealed that her fear stems from a road accident she survived aged 13, after the car she was travelling in was flipped onto its roof.

Following a four-hour drive to a show in Washington on Saturday, Perry wrote on her Twitter page: "Would have liked 2 have slept in car like every1 else, but since person fell asleep @ wheel when I was 13 & rolled car, no sleep in cars. Damn. (sic)"The star recently sparked rumours that she is engaged to boyfriend Travis McCoy.