Beyonce Knowles, above, and Leonardo DiCaprio's girlfriend Bar Rafaeli have been left reeling by a health alert that they might have been exposed to hepatitis A.

Beyonce Knowles, above, and Leonardo DiCaprio's girlfriend Bar Rafaeli have been left reeling by a health alert that they might have been exposed to hepatitis A.

Officials at the Los Angeles County Department of Public Health confirmed that an employee of celebrity chef Wolfgang Puck, who was working at a recent party the women attended, has been diagnosed with the disease.

All guests and staff at the Sports Illustrated Swimsuit Issue party on February 14 and all other events catered by Puck's company in Hollywood between February 1 and 20 have been advised to seek medical help immediately.

The health experts suggest that all those who might have come into contact with the sick Puck employee should get an immune globulin shot to prevent illness.

Meanwhile, a spokesman for Puck insists no one who attended Sunday's post-Oscars Governor's Ball, which the chef catered, is at risk. - Wenn