Exposure to Justin Timberlake provokes a number of symptoms: the mass purchasing of shiny pink hats; solidarity among women of all ages, united by a single cause; and shrieking to a decibel level that can drown out a stadium-sized PA.
For several hours last night and on Saturday the shrieking assaulted the eardrums of anyone who found themselves in the vicinity of the RDS in Ballsbridge, Dublin, where Timberlake played two sell-out concerts.
Every woman with blood in her veins was at the venue getting Justified, or at least that's how it appeared from the view in the Anglesea Stand.
On Saturday night, it was women as far as the eye could see, dressed to kill and with only one man on the mind. It was every hot-blooded single man's idea of paradise - 30,000 women, bedecked in their finest nightclub chic, and flushed with the prospect of a male encounter. The only problem was, if your name wasn't Mr Timberlake, you weren't getting so much as a batted eyelid. At the front of the trembling crowd, they were passing out water to try and temper the inflamed passions.
When Timberlake eventually made his appearance, rising from the centre of the colossal stage, the crowd left inhibition aside and plunged headlong into hysteria.
He had merely to raise a hand to elicit a torrent of adulation that dictators can only dream of.
Timberlake's Future Sex/Love Show world tour is something to behold. The sprawling stage was set in the middle of the RDS, with the crowd encircling it on all four sides.
A central platform splintered elegantly off into four smaller stages, with the ranks of Timberlake's backing band on either side, rising and falling on moving platforms.
Nine dancers competed with the 10-piece band and four backing singers for attention, but despite their astoundingly athletic collective efforts, all eyes were inevitably on Timberlake.
He worked every corner and each level of the stage, battling to keep the fans glued to every body-pop and side-stepped turn. He sang, danced, played and stoked and cajoled his band and crew into a searing performance of perfected pop sensibility that whipped the crowd into a collective, heated fever.
Funk-infused tracks, such as Cry Me a River, SexyBack and Rock Your Body, were given a blistering showing, and will linger long in the memory, despite his soul-pop renditions that see the mush mounting and mobile phones held aloft, with a few traditionalists bearing lighters.
At two ends of the sprawling installation were the "SexyBack" dance clubs, where fans with deeper pockets could pay to have a bar stool pulled up to the stage, or shake their thing within touching distance of Timberlake.
Halfway through the set on Saturday, Timberlake took a break from proceedings to get his round in for the band, and raised a Guinness toast to "Beautifully crazy and crazily beautiful Irish girls, and the best beer I've ever had".
Fair play to you Justin, and here's to the biggest, funkiest hen party in town.