This sculpture is called 'Veiled Christ' and was sculpted by Giuseppe Sanmartino. It can be found in the chapel of Sansevero. You can read more about it here: http://www.roguery.com/cities/naples/mystery/sansevero/sansevero.htm Rick Steves writes about it as well: http://www.ricksteves.com/plan/destinations/italy/sansevero.htm

Thanks a lot Jarrick !