Perhaps they really believe in the product, maybe they use it, or the money was too good to pass up.

Over the years, there have been numerous 'embarrasing' celebrity endorsements, or ones that just didn't fit the spokesperson.  See our list, courtesy of Fox News, of the 16 most embarrasing celebrity endorsements.  Maybe it will be Ahhhnold shilling soda in Japan,  Kirstie Alley pushing products for women who suffer from light bladder leakage (LBL) or Ozzie and 'I can't believe it's not butter.'