Former alcoholic Jack Osbourne is blaming the British royal family after he accidentally drank alcohol for the first time in three years. The son of rocker Ozzy Osbourne spent time in rehab in 2003 suffering addictions to drink and drugs, but recovered and has been clean and healthy since - until he accepted an invitation to PRINCESS BEATRICE's 18th birthday party last week (15JUL06). The 20-year-old has successfully avoided booze since turning teetotal, but claims he was unwittingly duped into drinking vodka at the bash. He says, "They brought out a strawberry jelly and didn't say it had vodka in it." Osbourne, who dressed as notorious London killer JACK THE RIPPER for the 1888-themed party, also takes a swipe at the snooty guests at the bash for Sarah Ferguson, The Duchess Of York and PRINCE ANDREW's eldest daughter. He adds, "The amount of posh people there was unreal. There were so many Eton schoolboys. I couldn't relate to them. I don't walk around wearing a ring with my family's crest on it and say, 'Woof woof!'"