We all do it. A celebrity--actor, athlete, whoever--appears on our television screen and tells us to do something, to support some cause, to buy a product. Because, you know, they use the product or support that cause, so we should too.
When that happens, I just like to remind myself that these are the same types of people whom we vilify for leading immoral, hedonistic lifestyles of sex, drugs, and rock 'n roll. We condemn these people for those actions and then turn around and succumb to marketing ploys that appeal to our admiration of these same people.
It's just another facet of our wonderful brain that we're able to reconcile such contradictory value judgements. ^_^
Anyway, I have to go purchase more things that a celebrity tells me will change my life because it changed theirs too. And they'd never lie to me for money, right?