The trend suddenly appeared on Twitter out of nowhere and left a lot of people wondering what it involved.
A little old band that goes by the name 5 Seconds Of Summer (5SOS) were in town last night performing at the SSE Arena and they clearly left an impact, with #SLFLBelfast accumulating well over 50k tweets.
Naturally, waves of teenage fans flooded the streets, the hotels and the arenas to see their 'future husbands' but the band was actually hiding out in French Village and in the Botanic area for most of the evening, totally oblivious to the fan fury happening in the centre of Belfast.
SLFL stands for the name of their tour, Sounds Live Feels Live and it must be very good live as they managed to sell every seat in the house. They also got the crowd going by playing a local favourite, Chasing Cars by Snow Patrol which was met with roaring cheers which you can see below.
Hopefully the boys come back soon, can't be coincidence it got very hot since they've been here.