HBO Harry Potter to give fans glimpse into new series with exclusive episode

The one-off special promises to take audiences behind the scenes of the highly anticipated series, which is based on JK Rowling's beloved novels.

A teaser for the programme was released on Thursday, featuring contributions from cast members including John Lithgow, who portrays Dumbledore, and Paapa Essiedu, who plays Snape.

Nick Frost, cast as Hagrid, narrates the special, which will be available on HBO Max across the US, UK and Ireland.

Mr Essiedu revealed that stepping onto the production's sets transported him back to childhood wonder. "Just walking in and seeing the real train... You imagine yourself being a kid at Hogwarts," the actor said of encountering the Hogwarts Express.

The 80-year-old Mr Lithgow, who takes on the role of the wise Hogwarts headmaster, described the franchise as an "extraordinary phenomenon" and spoke of the opportunity to expand upon the source material.

"To reimagine the Harry Potter canon, to let it breathe... We get to enact all the things that you know are going on in the wings but you don't see them," he explained.

Janet McTeer, portraying Professor McGonagall, was similarly moved by the elaborate production design. "Walking into the great hall that first time, you go 'Wow'," she remarked, later describing the series as "so beautiful".

The special will document the extensive search for the young actors to portray Harry, Ron and Hermione, with the roles ultimately going to newcomers Dominic McLaughlin, Alastair Stout and Arabella Stanton.

The casting process was remarkably competitive, with approximately 32,000 hopefuls auditioning for the coveted parts.

Production teams worked through an extraordinary volume of submissions, reviewing up to 1,000 audition tapes each day before settling on their final choices.

The teaser footage shows Dominic aboard the Hogwarts Express alongside Alastair, with the pair later joined by Arabella for a playful game of rock paper scissors.

Mr Lithgow reflected on the significance of the project, stating: "You wait forever to do something that means that much to people."

Production designer Mara LePere-Schloop described her involvement in the project as a "designer's dream", with the teaser showcasing the construction of elaborate sets including Hogwarts, Platform 9 and 3/4, and the shops of Diagon Alley.

"We're trying to get in the joy and the playfulness of what it means to be a magical kid," she explained, adding that the team is "adding a level of world-building beyond what the audience is familiar with."

The first season, adapted from Harry Potter and the Philosopher's Stone, will launch this Christmas, arriving earlier than originally planned.

Rowling serves as executive producer on the series, which aims to provide a faithful adaptation of her novels whilst expanding the wizarding world beyond what was depicted in the original film franchise.