Madonna is tipped as the new face of Max Factor, but there's no guarantee she'll behave
Advertising agencies call it the curse of celebrity endorsement. An international company picks a superstar at the top of their profession - Michael Jackson or OJ Simpson for example - to endorse a product. Then watches in horror when said celebrity suddenly becomes notorious for the wrong reasons.

One of the best examples is James Dean. Back in 1956, he uttered the immortal words: "I don't have the urge to speed on the highway" for a televised National Highways Committee advert, just weeks before racing to his death on the highway at 115 mph in his Porsche Spider, nicknamed "Little Bastard".

Now, cosmetics brand Max Factor is getting into bed with Madonna. It's the first time the material girl has endorsed a product since her Pepsi TV advert was pulled in 1989: the Like A Prayer promo - in which the infamous lapsed Catholic embraced a black Christ on the cross - upset the Bible belt stateside.

"We never discuss our negotiations with celebrities," says Max Factor spokesperson Andrea Witty, "particularly when fuelled by rumour and speculation. We haven't made a statement about Madonna". Max Factor's Garboesque silence on the Madonna TV campaign, directed by Alek Keshishian, is not purely PR hype. It is damage limitation.

Much has been made of the fact that Madonna has passed the age of 40. Her recruitment as a "face" has been lauded as a positive role model for older women in the youth-obsessed cosmetics industry. But after 14 years as the face of Lancome, Isabella Rossellini was fired - apparently because she had hit the big Four-Oh.

"They took my Lancome contract off me because I was 40," she was reported as saying. "I thought that was stupid because we were really successful. That's one part of fashion I really never understood. I think ageism in fashion comes from the big companies." But there was also the small matter of Rossellini's appearance in David Lynch's Blue Velvet, in which she graphically portrayed a masochistic gangster's moll. Controversy terrifies the grey suits and controversy is like cat nip for Madonna. The 40 issue is a red herring. By the time the airbrush has finished with most beauty adverts, there's little more left than eyes, nostrils, lips and hair. As February's cover of Harper's Bazaar shows, Madonna is heavily influenced by the "blank canvas" look of the geisha girl. Her face is a mask of make- up. Max Factor could choose Ann Widdecombe as its new face and make her look like supermodel Erin O'Connor: conversely, celebrities such as Madonna could be loose cannons. Take French actress and former face of Dior Emmanuelle Beart. In 1997, she lost her contract after being photographed on an anti-government march, sans make-up and in Swampy-style clothing. "Not appropriate behaviour", said Dior. Pretty girls, it seems, shouldn't be political. Helena Bonham-Carter was briefly signed as the face of Yardley, but after remarking that she rarely wore make-up, there was a mutual parting of ways. Despite remaining pursed-lipped about Madonna, Max Factor has been keen to remind the press of its movie star heritage. Rita Hayworth, Deborah Kerr and Loretta Young were all Max Factor girls in the 1940s and 1950s. More recently, Max Factor corralled make-up artists from movies Evita and The English Patient to sell its cosmetics to the stars. But the days of publicity department cover-ups of addiction, abortion and promiscuity are gone. When Johnny Depp and L'Oreal girl Kate Moss trash a hotel room, it is front-page news. It's a bit rich to hear Kate pronounce victory over split ends in a L'Oreal advert, then admit defeat over alcohol. When former Pepsi star Michael Jackson is accused of paedophilia, the public "have a right to know". A cosmetics house demands airbrushed morals, to match flawless complexions. But Madonna's skeletons are hardly in the closet. They are on video, in her glossy soft porn publication Sex and documented in biographies. Just because Madonna is now a mother and over 40 does not mean she will join the Union of Catholic Mothers and behave like a good girl. Madonna will continue to throw herself at everything she does. To become a passive "face of" doesn't quite work for the Boadicea of popular culture.