If there are specific rules to follow in order to become an international pop sensation, BTS – a seven-piece South Korean boy band who sing almost entirely in their native tongue – have broken every one. They are a largely internet-driven phenomenon, with a fiercely mobilised and diverse fanbase, but five billion streams on Spotify and number one albums here and in the US have made them impossible for the mainstream to ignore. Their appearance on Britain’s Got Talent last week, ahead of two sold-out shows at Wembley Stadium, felt like Simon Cowell desperately playing catch-up to a musical juggernaut that the industry has underestimated for far too long.

BTS seem to embody the borderless future of pop, in which language and genre will become purely incidental. Their first Wembley show – the first time the venue has hosted a Korean act – was a case in point. Segueing effortlessly between high-energy EDM, pastel-coloured pop and emotive balladry, BTS occasionally resembled a pick ‘n’ mix of their boy band forefathers – a New Kids on the Block arm-wave here, an *NSYNC body roll there – but with a soft and introspective sincerity that felt distinctly their own.

No expense was spared, with a stage that transformed into everything from a nighttime cityscape to an enormous lava lamp. Fire, a bouncy castle and two animatronic panthers made dramatic cameos, while the strongest of the show’s seven solo performances saw vocalist Jungkook soaring above the audience like a hunky Mary Poppins, swooping low enough to almost touch the teary, yearning fans beneath him, but always remaining punishingly out of reach.