<P> Hero Beauregard Fiennes - Tiffin ( born 6 November 1997 ) is an English actor best known for his role as the 11 - year - old Tom Riddle , the young version of antagonist Lord Voldemort ( played in the films by his uncle , Ralph Fiennes ) , in Harry Potter and the Half Blood Prince , the sixth installment of the Harry Potter films . He also played the role of `` younger Charlie '' in the war based film Private Peaceful . </P>
who plays young voldemort in the half blood prince
Hero Beauregard Fiennes - Tiffin