Doctors are urging Madonna, Demi Moore, Bruce Willis, and Gwyneth Paltrow to have a hepatitis shot as soon as possible after it emerged a barman working at Ashton Kutcher’s recent birthday party may have passed the liver disease onto them.

Kutcher celebrated his 30th birthday with a host of A-list stars at New York's Socialista club on February 7. But the New York City Health Department has warned a barman worked three nights at the venue when he was infectious with Hepatitis A - including Kutcher's 30th celebration.

Kutcher, his wife Moore, her ex-husband Willis, Madonna and Paltrow have now been warned there's a possibility they may have contracted the liver disease.

Last year, a sick member of celebrity chef Wolfgang Puck's catering staff inadvertently exposed stars including Drew Barrymore and Hugh Grant to hepatitis at a party following the launch of their movie Music & Lyrics.

And last February, Beyonce Knowles and the supermodel stars of the 2007 Sports Illustrated Swimsuit Issue were urged to get health checks after attending another Puck party, which featured the same Hepatitis A carrier among the catering staff.

(This news article provided by World Entertainment News Network)