Since the first movie’s release in 2001, the Harry Potter film franchise has featured a number of talented performers within its mᴀssive ensemble cast, which included Robert Knox. With so many characters in the original book series, choosing just the right actor to portray them on screen was imperative, whether it was the then-unknown child actors playing Harry Potter and co. or the British veteran actor royalty as Hogwarts’ professors.

While Harry Potter had several casting changes throughout the movies’ releases from 2001-2011, most of the actors stuck with their roles throughout the entire franchise. However, with many of Harry Potter‘s already established stars being older when the movies were filming, more than a few have pᴀssed away since filming wrapped. 2024 alone saw the loss of Minerva McGonagall’s Maggie Smith and the second Dumbledore, Michael Gambon. Gambon ᴀssumed the role in Harry Potter and the Prisoner of Azkaban, after Richard Harris, the first Dumbledore, pᴀssed away. Sadly, Harris wasn’t the only actor to die during the franchise’s run.

Robert Knox Played Marcus Belby In Harry Potter

Belby Is Invited Into The Slug Club Due To His Famous Uncle

Robert Knox played Hogwarts student Marcus Belby in the sixth film of the franchise, Harry Potter and the Half-Blood Prince. As a Ravenclaw, Marcus was one of the select few invited to Professor Slughorn’s Slug Club, an exclusive group founded by the Potions teacher. Marcus was hand-picked by Slughorn because of his uncle, a wizard named Damocles who invented Wolfsbane Potion. Unfortunately, Marcus has very little connection to his uncle, and barely knows him due to Damocles and Marcus’s father being estranged.

Once it was established that Marcus didn’t know his uncle well and didn’t appear to inherit his talent for potions, Slughorn lost interest in him. In the book, during the Slug Club Christmas party at Hogwarts, Marcus was witnessed by Harry to be handing out towels in the bathroom. In the film, Marcus is seen chowing down on sweets during the Slug Club meetings, which makes him the target of teasing by Slughorn.

Robert Knox Was Tragically Murdered In 2008

He Was Defending His Younger Brother Outside A Pub

As reported by People, Robert Knox was killed just days after filming Harry Potter and the Half-Blood Prince on May 24, 2008. Following an altercation at a London pub, 18-year-old Knox was stabbed five times with a knife while trying to protect his younger brother, Jamie. The attacker was 21-year-old Karl Bishop, who was sentenced to life in prison. Police reported that Bishop showed “no remorse” for his actions, and was quoted as saying “Yeah sweet,” when told he was being arrested for murder.

Following Knox’s tragic death, the actor’s father, Colin Knox, made an official statement, saying: “Rob was happy, outgoing and a fun person to be with. Rob always put everyone before himself, was always the first person to stand up against wrong. He achieved so much in his short life.” In a show of solidarity, the cast and crew of Harry Potter and the Half-Blood Prince wore ribbons to the film’s premiere in honor of Knox (via The Guardian). A documentary about Robert Knox’s death, тιтled (K)nox: The Robert Knox Story, was released in 2021, and a follow-up documentary is in the works, тιтled (K)nox: 16 Years Later (expected to arrive on YouTube in March 2025).

Robert Knox Would Have Returned To Harry Potter

He Was Set To Reappear In Harry Potter And The Deathly Hallows: Part 1

According to People, Robert Knox had signed on to be in Harry Potter: The Deathly Hallows Part 1, and would have reprised his role as Marcus Belby. Although the character was not mentioned in The Deathly Hallows novel, it is possible that Marcus might have made an appearance at Hogwarts, especially in the Battle of Hogwarts scene at the final movie’s climax, fighting against Voldemort and the army of Death Eaters.

In 2022, the cast and crew of the Harry Potter films reunited for a TV special on HBO Max, тιтled Harry Potter 20th Anniversary: Return to Hogwarts. The Harry Potter anniversary special included an “In Memoriam” segment, in which Robert Knox was honored along with late actors Richard Harris, Alan Rickman, John Hurt, Richard Griffiths, Helen McCrory, and others.