'Surprisingly brilliant': Millions flock to watch Harry Potter spin-off fan film

A Harry Potter prequel fan film depicting the rise of villain Voldemort has drawn the adulation of Potterheads, just days after it was posted online.

Voldemort: Origins of the Heir, produced and filmed in Italy by local production company Tryangle Films and released for free on YouTube over the weekend, has already been viewed more than six million times.

The 52-minute film follows four heirs of major Hogwarts houses and the transformation of student Tom Riddle into the infamous Dark Lord.

Countless viewers have flooded social media with praise for the production.

"Surprisingly brilliant performance by the team," wrote one on YouTube.

"Worth the wait...magnificent job according to budget," wrote another.

The film was produced following a successful crowdfunding campaign on a budget of approximately $23,000.

The campaign drew the attention of Harry Potter film rights holders Warner Bros, leading to a "private and confidential discussion" between the director and the studio.

Director Gianmaria Pezzato told video game website Polygon last year Warner Bros had permitted the team to continue with the film on one condition – they not attempt to monetize it.

"They let us proceed with the film, in a non-profit way," Mr Pezzato told Polygon via email.

Mr Pezzato said it was a curiosity regarding Voldemort's backstory that drove him to make the unofficial prequel.

"We wondered, ‘What made Tom Riddle become Voldemort?" he said.

"What happened in those years, and what really went down at Hogwarts when he came back?’

"There are some clues in the books which have not been transposed at all in the movies, but a lot goes unspoken."