[kls]

If your idea is good, it can make the difference, if it is bad people will see it for what it is celebrities using their position to get a pay day. I would personally only consider it after the market and your idea has some validation and at least a little bit of traction. If you have that kind of validation then you at least have something people want, which will come off as more authentic than a bunch of celebrities endorsing something that they don't use.