The professionals are worried: the power of the celebrity endorsement is closing in on the medical world, and it's not always with scientifically sound messages.
The combination of advice that is seldom right (remember Michael Parkinson's self diagnosis: "if you can pee against a wall from two feet you don't have prostate cancer"?) and the fact, as a new report highlights, "that celebrity endorsements act as signals of credibility that differentiate products or ideas from competitors and can catalyse herd behaviour," is a dangerous medical phenomenon.
The report describes celebrity medical advice as a "contagion," picked up through social networks in a desire to acquire "celebrities' social capital."
So anxious are the medics that The British Journal of Medicine today published a paper asking doctors to warn the public to take some of what the celebrities say with a large pinch of non-scientific salt.
If you remember Gwyneth, in 2007 telling a cancer conference she was eating biological foods to challenge "evil genes," you'll know to arm yourself with an even larger dose of celebrity cynicism.
The report's aim isn't simply an effort to make A-listers' role in medicine redundant though. Because while some famed do indeed offer bogus advice, others "wisely harness support for campaigns," says the British Medical Journal.
Michael J Fox's foundation has raised £215 million for research into Parkinson's disease, while Sir Elton John's charity has raised $300 million towards research into HIV and AIDS, and cervical cancer screenings doubled the year Jade Goody died of the disease.
"A better understanding of celebrity can empower health professionals to take this phenomenon seriously and use patient encounters to educate the public about sources of health information and their trustworthiness," concludes the report.