It’s time for Harry Potter fans to return to the wizarding world of Hogwarts as the first official teaser trailer for the reunion special has arrived. To celebrate the 20th anniversary of the release of Harry Potter and the Sorcerer's Stone, the film based on the first book in the extremely popular series by J.K. Rowling, HBO Max and Warner Bros. have brought the cast back together for Harry Potter 20th Anniversary: Return to Hogwarts.