Simplify the following text for a Grade 6 native English-speaking person.
Original: William Henry `` Bill '' Cosby , Jr. ( born July 12 , 1937 ) is an American comedian , actor , author , television producer , educator , musician and activist .
Simplified: William Henry `` Bill '' Cosby , Jr. , Ed . D ( July 12 , 1937 ) , known as Bill Cosby , is a famous American comedian .