From Tupac's performance as a hologram at Coachella to Audrey Hepburn's CGI advert for Galaxy chocolate , it's become increasingly common for stars to make digital reappearances after they die. Some celebrities, however, are taking steps to prevent this posthumous exploitation, with recently-uncovered documents showing Robin Williams to be among their number. According to the Hollywood Reporter, the late comic left provisions restricting the use of his likeness for 25 years after his death. This means that there won't be any films, adverts, or holographic stand-up gigs featuring Williams' voice or image until at least August 11, 2039.??