The addition of Diagon Alley to the theme park is expected to provide a boost for the park's revenues and for tourism in central Florida. It recreates the wizarding business district in London described in J.K. Rowling's popular book series and featured heavily in the subsequent Warner Bros. movies.
The new attraction expands the original Harry Potter world, which opened in 2010 and is modeled after Hogsmeade Village, which is located near the Hogwarts School of Witchcraft and Wizardry where the series' leading character Harry Potter begins his magical adventures.
Actor Tom Felton, who plays Harry's school nemesis Draco Malfoy, said Universal Studios' Diagon Alley attraction is better than the movie set he spent a decade filming on.
"It's far more immersive. There's no scaffolding, no green screen, no electricians standing around," he told Reuters.
Felton was joined by co-stars including Helena Bonham Carter, who plays the ruthless Bellatrix Lestrange and said the film series "gave me a job to come back to" after she took time away to have children.
The film's leading stars, Daniel Radcliffe (Harry Potter), Rupert Grint (Ron Weasley) and Emma Watson (Hermione Granger) did not attend on Wednesday night due to scheduling conflicts.
Author Rowling was also absent, although her latest book "The Silkworm," written under pseudonym Robert Galbraith, is set to hit stores on Thursday.
Diagon Alley will feature a new signature ride called "Harry Potter and the Escape from Gringotts," based on the magical goblin bank in the series. It is also geared toward eateries such as the Leaky Cauldron pub and souvenir shops, both of which drew bottleneck crowds at the initial Hogsmeade Village attraction.
Actor Warwick Davis, who plays Professor Filius Flitwick, said the new ride "surpassed anything I've ever seen before."
To visit both sections of the Wizarding World of Harry Potter, guests will have to buy a more expensive two-park pass, which costs $136 plus tax, because Hogsmeade and Diagon Alley were built in separate Universal parks.
The two attractions are connected by a train called Hogwarts Express, the magical locomotive that takes students to and from school in the "Harry Potter" series.
Comcast Corp's Universal Studios will also bring the world of "Harry Potter" to its Hollywood theme park in 2016, as part of its plans to drum up attendance with a revamp and five-year expansion plan for its film-themed attractions.