Luckily for them, the friend star jumped into the mob to give as many of its excitable members a hi-5.
The star's arrival didn't go unnoticed by the Metropolitan police either, who were quickly called to the fashion store to put an end to the commotion.
Jamie, who was dressed in his typically stylish attire - kitted out in one of Joshua Kane's sharp suits - thanked the police for 'coming out to today's fun loving event,' as he jokingly dedicated his post to the service.
And the actor couldn't resist showing off more of his boyish charm as he posed next to the police car in front of the store, clearly finding it amusing that he'd caused such a stir.