Arillegua Ortega's music is known for being danceable.  Upbeat, slightly shallow poppy jams that kind of all sound like each other.  (In actuality she does occasionally go for something a little slower, a little more dramatic.  She's actually classically trained, did you know, but -)

Arillegua Ortega's concerts are known for being wild spectacles, phenomena in their own right, full of explosions of glitter and explosives, half a dozen quickchanges, and a crazy stunt or two.  Tonight's is being filmed for a dual cartridge/microcart release, so people will be able to experience the wonder of an Arillegua show in the comfort of their own homes and without shelling out for tickets.

The tickets are not inexpensive and the security is not lax enough to be not annoying, but if you're into a particular kind of thing it is very, very a particular kind of thing.

So when a person appears quite conspicuously out of absolutely nowhere during the finale, backlit by a burst of pyrotechnics, the crowd goes pretty wild despite her initially undercostumed appearance.