Pictured: Rupert Grint's tears at funeral for murdered Harry Potter actor

Rupert, famed as Ron Weasley, welled up and brushed a tear from his cheek after the memorial service for the teenager who worked alongside him on the latest Potter film.

Robert, 18, will be seen by millions of Potter fans worldwide as Marcus Belby in the Half Blood Prince later this year, was fatally stabbed days after finishing the film.

He bled to death after being knifed outside the Metro Bar in his hometown of Sidcup, Kent, last month.

Mourning: A tearful Rupert Grint, who plays Ron Weasley in the Harry Potter films, at the funeral of fellow Hogwarts actor Robert Knox, 18

Also among the Potter actors at his memorial service yesterday was Alfie Enoch, who had laid flowers at the murder scene in memory of his friend after the killing.

Outside the church after the ceremony, Mr Enoch, who plays Dean Thomas in the Potter series, said: 'I can't really talk about what happened, it was a beautiful service.'

The stars of one of the biggest movie franchises in the world were among hundreds of friends and family at the public memorial service, which followed a private burial.

During the ceremony at St John's Church in Sidcup, Robert's grief-stricken father Colin told the congregation he had been living his dream as an actor when he was killed.

'He loved being part of Harry Potter and never stopped talking about it. It seemed like this might have been his big break, but just after it came he was taken away from us,' he said.

In pink: Robert Knox's mother Sally leads the way in bright colours at his funeral. She and younger son Jamie clutch each other for comfort by the hearse

His son had loved the filming, he recalled, telling mourners: 'He told us about one scene he filmed where they had to do numerous takes of him eating a profiterole.

'When they'd finished and done with the filming, he felt very sick. He later told me "It would've been no problem at all if it had been glasses of lager'".

Mr Knox also revealed he was is in line for a postumous police bravery award after helping to track down criminals at a shopping centre where he worked, exactly one year before he died. 

Support: The pair share a tearful hug before the hearse makes its sombre way to the crematorium for a private family ceremony

Robert's close friend Callum Turner had the congregation in fits of laughter during his tribute, in which he recounted the time Robert had slapped a policeman's bottom by mistake while out driving shortly after passing his test.

He said Rob had wound down his window and slapped a waiting cyclist's bum while stopped at traffic lights.

But he was stunned to be told by his 'victim' that he was a serving cop when the pair met again at the next set of signals.

Devastated: Robert's heartbroken father Colin lays a hand on the hearse

In sombre scenes during the service, family friend and musician Charlie Coxill sang an adapted version of Bob Dylan's Knockin' On Heaven's Door - with one verse changed to 'Put these knives in the ground, we don't use them anymore'. 

And a choir from D&B School of Performing Arts - Rob's old drama school - performed Oasis' Wonderwall, a song the slain teen sang with rugby team-mates at Sidcup to help them get psyched-up for games.

Friends and family were under strict orders to wear only bright colours at his final farewell and many turned up in pink shirts and ties in tribute to the teen's sense of fun.

His mother led by example by wearing a bright pink bolero-style cardigan, matching shoes and a polka dot dress.

A tribute-laden cortege led by a grey Rolls Royce made its way from the family home followed by dozens of his close friends and family ahead of the service.

Before it set off, Mrs Knox and Robert's younger brother Jamie stood close by the hearse with their hands clutched and their heads bowed in sorrow.

Tragic: Robert (right) with his brother Jamie and mother shortly before his death

A mourner, who did not want to be named, said: 'Rob would've wanted us not to be
sad, but it's impossible not to be on a day like this.'

The teenager, who had been an actor since the age of 11, completed filming the latest Harry Potter movie five days before his death and had signed to appear in the next film.

He had also appeared in The Bill, the 2004 film King Arthur, and alongside actor Nicholas Lyndhurst last year in BBC sitcom After You've Gone.

It is believed he was trying to protect his younger brother Jamie, 17, on the night he was killed.

His death on May 24 brought the total number of teenagers murdered in London this year to 14.

• Karl Bishop, 21, of Carlton Road, Sidcup, has been charged with Robert's murder and wounding with intent. He is due to appear at the Old Bailey in September.