single word to describe someone famous who uses their fame to push their personal agenda. Example is sports or entertainment celebs pushing their political/environmental/equal rights agenda
Ed (a famous sportsman) is a xxxxxxxxxx for using his fame to promote his political views
I have done many searches revolving around one using their position to advance their personal agenda. The closest word I've found is opportunist – although that doesn't seem to describe the extra influence that fame contributes to it.
Best Answer
The common phrase I've seen for this is "celebrity activist"--see news examples here at Huffington Post. Google searches also return this phrase in tabloids and pop culture magazines.