His excellency The ambassador of a brand

Almost all of us , who have'nt been livign under a rock, have seen a celebrity endorsement of a product. Naturally if a celeb can use a product, its certainly good enough for me.
Maybe a decade back, I heard the term brand ambassador being bandied about. Usually it was to assosciate one celeb in particular with the brand, and the brands were usually premium brands(at least by Indian standards). The term ambassador, had to stand for something regal right? Wrong. I just read that Priety Zinta has been decalred a "Brand ambassador" for something as mundane as Rexona Deo.
For the life of me I can't figure out how a deo will make its way into a classy converstaion.
"Damn , have u heard of deo" doesn't count. Nor can I quite imagine anyone associating apreety lass like Priety with deo either. "God Priety makes a perfect ambassador for Rexona Deo, she sweats like a hound dog on a hot summer day , but u can't tell, cos she has a life time supplyy of rexona deo".
So marketing folks who make a lot more than I do, take a moment and maybe a breath or two, before u decide to get a brand ambassador for the next ,mousetrap.