AceShowbiz - Kelly Osbourne endured the "worst day" of her life while shooting scenes for new movie "So Undercover" on Tuesday, January 4, after she fell sick on set. The rock offspring is hoping to launch a movie career by starring alongside Miley Cyrus in the action comedy, but work on the film has been hampered by a vomiting bug which has affected a number of cast and crew.

Osbourne was among those struck down by the illness and her symptoms became so severe she was put on an intravenous drip to replenish fluids. In a post on her Twitter.com page, she writes, "I'm still actually really sick so are 3 other girls God please help us get through this day!"

"Finally done for the day 3 bags of IV fluid later we all dropped like flys thanx (sic) so much to production team 4 looking after me so well! Having 2 film a party scene while trying not to s**t ur (your) tights and puke at the same time = worst day of my life."