Up-and-coming actor Rob Knox was killed during an altercation outside a bar

Rob Knox – an 18-year-old actor with a role in the upcoming Harry Potter movie – was stabbed to death last weekend in a fracas outside a South London bar.

A 21-year-old man has been charged with the murder and will appear at a preliminary hearing later 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 in the early hours of Saturday morning from internal bleeding. 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.”