When that happens Monday, "Phantom," dethrones another Lloyd Webber musical, "Cats," which closed after 7,485 shows, the New York Daily News reported Wednesday.
Monday's audience will be studded with stars and will be followed by a lavish masked ball at New York's Waldorf-Astoria, the Daily News said.
Lloyd Webber told the Daily News he was both proud of the milestone and surprised as well.
"You could never predict something like this," he said. "It's extraordinary, really. It's absolutely fantastic from 'Phantom's' point of view. From 'Cats' point of view, well, I'm very glad that 'Phantom' is the one that passed it by."
The $8 million production of "Phantom" opened at the Majestic Theater on Jan. 26, 1988. It won seven Tony Awards, including best musical and best actor for Michael Crawford.
More than 11 million people have seen it on Broadway alone, where it has grossed $600 million, the newspaper said.