Tragic documentary about death of Harry Potter star Rob Knox has left viewers 'in tears'

Viewers were left 'in tears' after watching a documentary about the tragic death of Rob Knox.

The Harry Potter star - who played Marcus Belby in Harry Potter and the Half-Blood Prince - was stabbed to death in 2008.

He was just 18 and had his whole career - and life - ahead of him.

Described as a 'typical teenager with a great sense of humour', he had already starred in the likes of ITV police drama The Bill, Channel 4’s reality show Trust Me, I’m a Teenager and the BBC comedy After You’ve Gone.

Though his breakthrough role came in the Harry Potter franchise in the sixth instalment, released posthumously in 2009.

Sadly, Knox was killed defending his brother on a night out in Sidcup, London, in May 2008.

Following his death, ITV commissioned a documentary titled (K)Nox: The Rob Knox Story in 2021.

Take a look at the trailer below:

Knox was out celebrating his big acting break out in Bexley when he found out that his brother had been threatened at knifepoint.

When he and his friends rushed over to disarm the perpetrator, Rob was stabbed and killed.

Karl Bishop, who was 22 at the time, was found guilty of stabbing Knox five times.

Considered a highly dangerous man, Bishop was handed a life term with a minimum sentence of 20 years before parole.

Rob Knox played Marcus Belby in Harry Potter. (Warner Bros.)

Mr Justice Bean said: "I do not think it is proved that you intended to kill Robert Knox.

"The truth is that you simply could not care less whether you killed him or not.

"Your lack of regret let alone remorse was truly chilling."

The documentary follows what happened in the lead up to the tragic event as well as how the family were managing their grief and anger while being in the spotlight.

Viewers have since been left in tears after watching the doc, as one person wrote: “Watched this last night. What a moving and emotional documentary.”

A second added: “Cried all the way through. So so so sad. RIP Rob.”

“Doesn’t matter how many times I watch it… I am bawling my eyes out every time,” a third commented.

Daniel Radcliffe said he was 'devastated' by his co-star's death. (ITV)

At the time of Knox's death his co-star Daniel Radcliffe, who of course plays Harry Potter, said: “Dear Rob, We are all proud to have known you and devastated to have lost you. It is terrible just to write this note. Rest in peace, Dan xxx.”

The actor’s parents, Sally and Colin Knox, said: “Rob was kind and thoughtful and would always help out others - he would spend his last penny on other people instead of himself.

“The life and soul of the party, he was very outgoing, loved sports, and would always strike up a conversation with people.

“He was respectful to others and adored by his family and friends.”

(K)Nox: The Rob Knox Story is available to watch now on ITVX.