A 21-year-old man has been charged with the murder and will appear at a preliminary hearing Tuesday, Scotland Yard confirmed to PEOPLE.
Knox, described as "a kind and thoughtful son" by his parents, has a small role as Marcus Belby in Harry Potter and the Half-Blood Prince (slated to be released this fall).
The teenager died from internal bleeding in the early hours of Saturday morning. Three of his friends also suffered knife wounds in the dispute.
"Rob was happy, outgoing and a fun person to be with," his father Colin said in a statement. "Rob always put everyone before himself, was always the first person to stand up against wrong. He achieved so much in his short life."