@2222:
Somehow, the question confused me…
"what" refers to "thing", as porn star is human, the question should be "who".
When I read the question, I thought it would be like porn actor have some kind of star or porn actor's stars (zodiac)...
I guess the title need to be edited.
Good point 2222,
Some people like me are still learning English, and sometimes we learn wrong things and grammar rules because the web is probably our main way of contact with this language. Today I learnt a new thing from this explanation.
By the way, my favorite porn stars are Gabriel Clark Lenfant, Vander (Chaosmen), Jamie, Tanner, Jarek, Ryan, Brandon, Pavel and Daniel (from Sean Cody), Trey, Josh, Quinn, Aiden, Chandler, Hunter, Sean, Zeb and Lucas (from Corbin Fisher), Dan Fisk and Robbie Rojo.