The show, which cost $24.9 million and features 17 pneumatic lifts beneath the stage, began previews in May, the BBC reported Tuesday.
The production debuted in Toronto last year but was cut by about 35 minutes for the West End opening after it wasn't well-received by critics.
Director Matthew Warchus called the show a "hybrid of text, physical theater, music and spectacle."
"To read the novel is to experience the events of Middle-earth in the mind's eye; only in the theater are we actually plunged into the events as they happen," he told the BBC. "The environment surrounds us. We participate. We are in Middle-earth."
The show runs three hours and has a cast of 50 who use more than 500 pieces of armor, the BBC said.