On Saturday night, a singer with a 13-year career played only her second London headline show. Naturally, the venue was packed out with rapt, merchandise-clad fans eager to see her live. But “live”, in this instance, is a loose concept – because Hatsune Miku is a hologram, or virtual idol.

Miku’s name comes from a blend of the Japanese words for “first”, “sound” and “future” and the turquoise-haired avatar was created by Japanese software company Crypton, as the face of Yamaha’s Vocaloid software, in 2007. Independently produced freeware can be downloaded by anyone and used to create a song in Miku’s piercingly sweet vocal. In terms of her tracks, she’s the world’s first crowdsourced pop star. Her setlist pulled from the more than 100,000 songs that have been made in Miku’s name, and that have amassed an international fandom that has propelled her to performing on the Late Show with David Letterman, a Lady Gaga tour, and this year, even at Coachella.

Full throttle experience … Miku at Brixton. Photograph: CFM/Sega

Seeing these tunes performed is a full-throttle experience. Miku is accompanied by four human musicians who are indefatigable, playing for two breakneck hours with a singer who has no need to pause for water breaks, costume changes or banter. Miku marches through J-pop, dance and nu-metal, bringing out other virtual idols as her special guests. While Miku is confined to a transparent screen centre-stage, a high-octane light show carries her energy around the auditorium for highlights such as the mosh-heavy thrasher Hyper Reality Show, and the punchy power pop of Rolling Girl.

As a concert, it’s oddly sterile, with none of the unpredictability or imperfections that make live music thrilling. But tellingly, the tour is named the Miku Expo, and the London show resembles more a real-life gathering-slash-rave for online devotees than a traditional gig. Many in the audience are dressed as Miku, and many more have purchased official Miku glowsticks, which they wave in religious unison throughout the entire set as a visual reminder of the community and collaboration that creates Miku’s numbers. She may not be the future of live music, but she represents a potential future for music creation and fandom, and internet culture’s blurring of the lines between the two.