Q: Is Sarah Jessica Parker really wearing Garnier Nutrisse Champagne Fizz #82, as the fine print in the ads in my fashion magazines claims? If so, did she have to re-create the whole at-home hair-coloring experience by going out to her local CVS and buying it (maybe with a coupon?), donning the little plastic gloves and applying it herself in front of her 50,000-watt bathroom mirror?

Julie Mendelson, Arlington

A: In a 1980 revision of endorsement guidelines, the Federal Trade Commission indirectly countered the clandestine "does she or doesn't she?" quality of hair-coloring claims of yore -- and any other consumer product that celebrities might endorse. Thanks to Section 255.1, if "the advertisement represents that the endorser uses the endorsed product, then the endorser must have been a bona fide user of it at the time the endorsement was given. Additionally, the advertiser may continue to run the advertisement only so long as he has good reason to believe that the endorser remains a bona fide user . . . "

Parker has been shilling for Garnier Nutrisse since 2000, and clearly they've put her usual rooty frizzle through some radical shades of change. Ever a dutiful employee, she has let it slip here and there that she really can and does color her hair at home once in a while.

But anyone who has ever seen a cheeseburger readied for its close-up on a commercial shoot knows that it would be crazy to allow the cheeseburger to go on camera without the assistance of several stylists. (There's one person whose job it is just to spray the bun with shellac.) Parker's a mom on the go, and she's got places to be and people to do her hair when it needs to be done -- such as on the set of her new Gap jeans ad. The FTC is unclear on whether or not we're supposed to believe she really customizes her own jeans and enjoys the company of Lenny Kravitz so much. Some things you just have to take on faith.

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