An act not entirely appreciated by a 20,000-strong audience of doe-eyed 6-11-year-olds on a school night curfew. The reason? Apparently because of 'technical difficulties'. And definitely not because he was having a quiff crisis/was too busy playing computer games/doing a personal appearance for £300 a pop just hours before/other (delete as applicable).
Parents fumed and children sobbed, and literally threw toys out of their prams. Some had to leave before even getting a glimpse of their newly-biceped, barely-pubescent idol.
Was it Bieber's fault? Apparently not. But the fans who have continually topped up his lardy £36 million piggy bank deserve a little more than a few prickly tweets off him and a half-hearted apology.
Forking out up to £70 for tickets to have a slice of Bieber pie, the crowd booed as they waited for the singer's arrival, with many parents - most fans probably not au fait with mobiles yet - enraged that they missed trains home, were left stranded and with tired kids after Bieber finally emerged at 10.30pm.
It must have been panic attacks all round at Bieber HQ and sources claimed he was having a hissy fit before he went on stage, which his PR team denied. Team JB further angered the crowd by simply tweeting an apology for his no-show - they didn't even get offered a free drink/glass of milk at the bar.
Parents have taken to Twitter to vent their frustrations saying they are 'absolutely livid', 'appalled' by this treatment of his young fans and insisting a refund 'won't compensate the emotional damage he has done'. Slightly dramatic, maybe. But try fobbing that excuse off to few thousand heartbroken kids.
The 19-year-old former YouTube star tweeted his own not-so-heart-felt apologies the next day and wrote:
And that's the end of that. Or so he thought. Has he lost the pop plot or is he just acting like any normal young lad - albeit one who found international fame aged 13 and drives round in a penis-extending white Ferrari?
All this puberty-fuelled 'bad boy' behaviour; the tattoos, seen with a 'suspicious looking cigarette', the 'cut Bieber' trend on Twitter which he remained silent about, death-threat fans, new-found finger flashing, his recent diva-esque tantrum on his 19th birthday, driving round like royalty flying the Canadian flag, 'groping' that fan, refusing to meet competition winners.
And the ultimate tell-tale sign he's gone a bit, er, potty? Wearing a gas mask to go down the shops.
The night of O2-gate, surely The Bieb could have popped his head round the stage curtain and given his fans a wave? 'Technical faults' don't prevent pop stars from signing a few autographs or giving their loyal fans a bit of thumbs-up photo action. Even a bit of sulky moonwalking in his three-sizes-too-big-trainers would have been better than radio/record silence.
Someone needs to tell him to pull his socks - and trousers up, god forbid he shows off any more groin - take off his gas mask and have some respect for his fans. Then hook him up with the boys from 5ive and a copy of Kerry Katona's Too Much, Too Young quick smart.
And to really custard pie the audience's faces a bit more, when Bieber eventually descended on the teary, now expletive-riddled crowd, he was dangling from the sky strapped on to a pair of angel wings. But by this time, the halo had well and truly fallen off.
Do you think success has gone to his perfectly-coiffed head - or is he still the teen king of cool?