Perusing the most recent Vogue, I could not help but notice the plethora of famous faces staring back from the pages, and not just from the editorial photo shoots. Every other ad displayed a familiar face: Scarlet Johansson for Dolce & Gabbana Cosmetics, Madonna for Louis Vuitton, Cate Blanchett for SK-II skincare, and so many more. Usually these star-studded ads go unnoticed specifically because they are so typical. Celebrity endorsements are the name of the game in the fashion world and beyond, and companies that have never used celebrities before are jumping on the endorsement-bandwagon with increasing rapidity.

Women’s Wear Daily announced this week that the CEO at design house Emanuel Ungaro is planning on reviving the brand’s ad campaign with a celeb mug, and the most discussed celebrity is none other than Lindsay Lohan. Not only did we think it impossible for Lohan to be even more overexposed, but the pairing also raises the question: why?

The possible LiLo-Ungaro coupling highlights the head-scratching randomness of so many celebrity endorsements. While most advertising done at large companies is meticulous researched, involving talks of “target demographics,” pie charts and focus groups, the choice of which celebrity to use for which fashion ad seems wildly unscientific.

Take Madonna’s stint as the face of Versace back in 1994. The decision to bring Madge on was made over dinner at Cipriani where Donatella Versace, famed fashion photog Mario Testino and the Material Girl herself shared a most pleasant evening. So pleasant, in fact, that the three decided to reunite, and Donatella released the statement saying simply, “When we feel there is a connection and the synergies work, then we make it happen.”

Sometimes such creative-type gut decisions work- tellingly, Madonna returned to shoot another Versace campaign in 2005. When a celebrity whose image fits naturally with the personality of a brand, the pairing has a natural feeling of inevitablity, like a happy marriage— think Gwen Stefani for Harajuku Lovers, Pam Anderson for Vivienne Westwood, Gwyneth Paltrow for Tod’s, and the sexy David and Victoria Beckham for Armani. (Victoria’s other famous endorsement for fashion darling Marc Jacobs consisted of wildly creative ads by the inventive Juergen Teller. The memorable campaign rendered the question of Beckham as a sensible Marc Jacobs partner a moot point- no one could stop raving about the ads, perfectly accomplishing the purpose of celebrity endorsements in the first place.)

Sometimes, though, companies get it wrong. I’m sure no one remembers the Sarah Jessica Parker ads for GAP from 2004. Who better to promote all-American khaki than… Carrie Bradshaw? The pairing was all wrong, and GAP and SJP parted ways after 9 months. Similar “divorces” are common as companies move on to the newest and hottest faces. Paradoxically, celebrities, whose literal value in dollar-amounts makes them so appealing to advertisers, are quite disposable. The nature of their value is ephemeral, as it is based on popularity and recognition rather than enduring qualities. It seems that the best celebrity-corporate marriages are the result of a shared personality and identity that lends the endorsement real weight.

What do you think- are you more likely to buy something with a celebrity endorsement?