NEW YORK - The official rules of football could not be much clearer: “Players are entitled to an interval at halftime, not exceeding 15 minutes.”

And the lineup for July 19’s inaugural halftime show at a World Cup final could not be much fuller: Madonna, Justin Bieber, Shakira and BTS as headliners, plus Burna Boy, a Staten Island elementary school chorus and the New York Philharmonic, conducted by Gustavo Dudamel.

Get ready for tradition to be tested.

FIFA, the World Cup’s organising body, approved a halftime show in hopes that it would attract more casual fans during a championship match between Spain and Argentina that is expected to exceed more than 1 billion viewers – five times the audience of the Super Bowl.

But purists consider the show sacrilegious, another example of what they say is catering to corporate interests by FIFA in a tournament hosted by the United States, Canada and Mexico. It was expanded to 48 teams, featured abnormally high ticket prices and added mandatory hydration breaks that were used by some broadcasters to air advertisements.

Football is meant to be a continuous pressure-filled environment with minimal interruptions, said John Williams, a sports sociologist in Britain. Fans expect discussion of formations and fitness while players are recuperating during the afternoon halftime break, not a star-studded concert.

“It will just change the whole character of the event,” Williams said. “It won’t feel right.”

Guy Carrington, a producer at Done+Dusted, a live entertainment event company helping to produce the halftime spectacle, said preparations for the show had been an exercise in restraint.

“This is about creating an entertaining halftime show,” Carrington said, “but it’s also about doing it within the boundaries and to make sure it doesn’t feel out of place, and that it leaves the pitch exactly as we found it.”

To protect the field at New York New Jersey Stadium (the temp...