Mexico City police officials are on high alert in preparation for Monday's Justin Bieber visit.
The crowd limit for the Central Plaza free concert has been set at 80,000, but local officials fear hundreds of thousands of fans will turn up for the show.
Reports suggest 6,000 police officers will patrol the event and attempt to control the crowds, while others will oversee the gig from police helicopters.
Giant screens have been erected in streets near the concert site, so that fans who fail to get access to the actual music venue can still watch the Baby hitmaker perform.
Bieber's most recent whistle-stop promotional trip to Europe suggests the police officials are wise to be prepared for fan chaos on Monday - the pop idol was mobbed by fans in Norway, France and England.