Vaughn was born in Paddington, London, England. Until 2002, he had thought that he was the child of a relationship between his mother, Kathy Ceaton (died 20 July 2013), and American actor Robert Vaughn. A paternity investigation in the 1980s revealed that Robert Vaughn was not his father, but Ceaton had never revealed otherwise to Vaughn. Upon asking his mother about his true paternity, she revealed that his father was George Albert Harley de Vere Drummond, an English banker. Early in Vaughn's life, before the paternity investigation, Robert Vaughn had asked for the child's surname to be Vaughn, and it continues today as Vaughn's professional name, though he now uses de Vere Drummond in his personal life, having changed it by deed poll in May 2002.
Vaughn was educated at Sussex House School in London and then Stowe School in Buckingham. Taking a gap year between Stowe and university, he travelled around the world on a Hard Rock Cafe tour. After arriving in Los Angeles he began working as an assistant to a film director. He later returned to London, and attended University College London studying anthropology and ancient history. He dropped out after a few weeks.