You probably recognize his face from a single, slightly awkward dinner scene in a wizarding castle. He’s the kid aggressively eating chocolate pudding while Jim Broadbent’s Professor Slughorn tries to make small talk. That was Rob Knox. He played Marcus Belby in Harry Potter and the Half-Blood Prince, and for most of the world, that’s where his story begins and ends.
But there’s way more to the Rob Knox movies and TV shows list than just a seat at the Slug Club table.
Rob wasn't just some lucky extra who stumbled into a massive franchise. He was a working actor from Southeast London who had been grinding since he was 11 years old. He was talented, funny, and—by all accounts from the people who actually knew him—a genuinely brave person.
The story of his career is often overshadowed by the horrific way his life ended in 2008. It’s a heavy topic. Honestly, it’s impossible to talk about his work without acknowledging that he never got to see his biggest role hit the big screen.
The Early Days: Before Hogwarts Called
Long before the wands and robes, Rob was just another kid from Sidcup trying to make it in the UK acting scene. He wasn't a "overnight success" type. He did the work. He went to Beths Grammar School and spent his weekends at the D&B Theatre School in Bromley.
His first real credit was on the long-running ITV police drama The Bill. If you grew up in the UK, you know The Bill was the ultimate rite of passage for young actors. It was gritty, it was fast-paced, and it was where you learned how a professional set actually worked.
Then came the reality TV stint. No, not Big Brother. In 2003, he appeared in a Channel 4 show called Trust Me, I'm a Teenager. It was one of those social experiment shows where kids were given power to see if they could actually handle it. Rob was just 14. You could already see that he had a certain "it" factor—a natural comfort in front of the camera that most kids his age lacked.
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Rob Knox Movies and TV Shows: A Growing Portfolio
People often forget that Harry Potter wasn't his first movie. In 2004, he landed a bit part in the big-budget epic King Arthur. He was an extra, sure, but being on a set of that scale—starring Clive Owen and Keira Knightley—was a massive deal for a teenager.
Around 2007, things really started to pick up speed. He landed a role as "Josh" in the BBC sitcom After You've Gone. Working alongside comedy veterans like Nicholas Lyndhurst (of Only Fools and Horses fame) is no small feat. He appeared in two episodes, proving he had the comedic timing to hold his own next to industry heavyweights.
Then, the big one happened.
In late 2007, he was cast as Marcus Belby. Belby wasn't a main character, but in the Potterverse, there are no "small" roles. He was the nephew of Damocles Belby, the wizard who invented the Wolfsbane Potion. That lore mattered to fans.
Why the "Pudding Scene" Worked
The scene in the Half-Blood Prince where Slughorn introduces Belby is genuinely funny. Jim Broadbent later recalled that he actually gave Rob advice on how to pace himself with the dessert because they had to do so many takes.
Rob didn't listen.
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He kept shoveling the pudding in, commitng to the bit with everything he had. Broadbent eventually admitted that Rob was right—the sheer gluttony of the character made the scene perfect. It provided a much-needed moment of levity in what was a pretty dark film.
The Role That Never Was
Here is something most people get wrong: they think Rob was just a one-and-done character.
Actually, Rob had already signed on to return for Harry Potter and the Deathly Hallows. Even though Marcus Belby doesn't really appear in the final book, the producers liked Rob’s performance so much they wanted to bring him back. He was supposed to be part of the final stand at Hogwarts.
He never got the chance. On May 24, 2008, just days after he finished filming his scenes for the sixth movie, Rob was stabbed to death outside the Metro Bar in Sidcup. He wasn't looking for a fight. He was protecting his 17-year-old brother, Jamie, from a man armed with two kitchen knives.
It was a senseless, brutal act that robbed the industry of a rising star and a family of their son.
(K)nox: The Rob Knox Story (2021)
For years, his story was a tabloid headline about "The Harry Potter Murder." But in 2021, a documentary titled (K)nox: The Rob Knox Story was released to set the record straight.
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This isn't just a true crime doc. It was directed by Aaron Truss, a childhood friend of Rob’s, and produced by Rob’s father, Colin Knox. It features interviews with the cast, including Tom Felton and Jim Broadbent, who talk about Rob not as a victim, but as a colleague.
The title is a clever, if heartbreaking, nod to the "Nox" spell in the Harry Potter world—the spell that puts out the light.
What the Documentary Revealed
- The Cast's Reaction: Daniel Radcliffe and Emma Watson weren't just "sad"; the entire set was paralyzed. At the London premiere of Half-Blood Prince, the cast wore white ribbons on their wrists as a tribute to him.
- The Unseen Footage: The doc features home movies and behind-the-scenes clips provided by the family. It shows a kid who was constantly making people laugh.
- The Legacy: It highlights the work of the Rob Knox Foundation, which focuses on street violence and knife crime prevention in the UK.
A Legacy Beyond the Screen
It's easy to look at the list of Rob Knox movies and TV shows and feel like it’s too short. It is. But the impact he left behind is surprisingly large.
Because of the "Harry Potter actor" tag, his death received international attention that other victims of knife crime often don't get. His family used that platform to push for change. They didn't want him to be a statistic; they wanted his name to mean something.
Today, the Rob Knox Film Festival helps young filmmakers get a start in the industry. It’s a way of continuing the career that he was never able to finish.
Actionable Insights: How to Honor the Memory
If you're a fan of the franchise or just someone moved by his story, there are ways to engage with his legacy that go beyond just watching the movie:
- Watch the Documentary: (K)nox: The Rob Knox Story is available on various streaming platforms (like ITVX in the UK). It provides a much more nuanced look at his life than any Wikipedia page ever could.
- Support the Foundation: The Rob Knox Foundation does real work with young people in London, using drama and sports to steer them away from street violence.
- Watch His Early Work: If you can track down episodes of After You've Gone or The Bill, do it. It’s worth seeing the range he had before he became "the kid with the pudding."
Rob Knox was an eighteen-year-old with a contract for the biggest movie franchise in the world and a talent that was just starting to bloom. He wasn't just a character in a movie; he was a guy who stepped in to save his brother. That’s the role he should be remembered for most.