Kelly Osbourne once had a foot-long Subway sandwich thrown at her head.

Kelly Osbourne

Kelly Osbourne

The 32-year-old reality TV star shot to fame in 2002 when her famous family invited the cameras into their home for their show 'The Osbournes' but she has admitted she wasn't prepared for the scrutiny she'd receive over her weight and remembers vividly one time when a cute guy asked her to roll down her car window, which she assumed was to ask for directions, in Los Angeles and he launched the messy roll at her.

Recalling the moment in her new autobiography 'There is No F***ing Secret: Letters From a Bada** B***h', obtained by DailyMail.com, she said: "Instead, he threw a foot-long Subway sandwich in my window, which hit me on the side of my head and exploded. Then he called me fat b**h and sped off."

Kelly's friends tried to persuade her to report the incident but she refused because she thought the police would laugh if she told them she'd been assaulted by a sandwich.

The memoir documents Kelly's childhood and life in the spotlight, as well as her famous father Ozzy Osbourne's battle with drugs and alcohol and how he relapsed when her mother Sharon was diagnosed with colon cancer in 2002.

She explained: "Whenever something bad happened, like when my dad would start using again or mum was diagnosed with cancer, I was convinced that it was 100 percent my own fault, even if it was entirely out of my control ... Dad was there in his boxers [when Sharon got her diagnosis], and I watched him scoop his hands into a bowl of pills, swallow a handful of something, and then wash it down with vodka."

Although she could see how much drugs had taken over her dad's life, Kelly turned to the substances herself when her mother was fighting for her life in hospital and Ozzy was lying in a coma in a hospital in the UK following an ATV accident.

She said: "I watched both of them come out of surgery and flatline and die in front of me and get brought back to life. Drugs became my solace and --- if I'm being totally honest--- probably the only thing that kept me going. With every pill I popped, I retreated more and more into my black hole of self-hatred."

Kelly finally managed to beat her demons by her mid-twenties after numerous stints in rehab, years of therapy and a brief period of time in a mental institution.