Ask HN: Value of a Highly Visual Advocate

I'm working on a consumer based early stage web app which has received interest from a highly visual TV/Athlete (2+ million Facebook followers and within our demographic) to help advocate our product...for a price(cash or equity). I am confident we can grow our business to the point at which we won't need that type of endorsement but checking to see if anyone else has worked out agreements with such advocates? Almost as though Ashton Kutcher wanted to invest in us.