I’m looking for first name “J” and last name “R,” as suggested by the examples in the OP of Joan Rivers and Julia Roberts.
What do you mean by up to date? Alive?
Jonathan Richman
Joey Ramone
Joseph Ratzinger
Jerry Rice
James Earl Ray
Janet Reno
Jonathan Rhys-Meyers
Jack Ruby
Alive is good – hip is good – so of Joey Ramone, Jerry Rice, and Janet Reno, the winner is clearly Jerry Rice. Who’da thunk? 
He even goes by JR, so I say he wins the topic.