Who was the first true "Hair Metal" act?

I have narrowed down between Bon Jovi and Def Leppard but I may be mistaken. I know that Bon Jovi was inducted into the UK Rock and Roll Hall of Fame and I'm sure they'll be in the US Hall as well. But, I as a kid really remember all cool Def Leppard vids like "Photograph" and "Rock of Ages" So, I guess I'm not sure who takes the crown. For all I know I could be someone else entirely. Thanks in advance.