The 22-year-old's apparent lip syncing left his listeners disappointed and upset, and taking to Twitter to vent their outrage.
Loved #VFestival, but #JustinBieber was the worst performer I've ever seen live- miming 95% & terribly. Lazy, disappointing & insulting,' one fan tweeted.
'I think @vfestival forgot to turn @justinbieber's mic on tonight... P**s poor live set from bieber,' a concert goer blasted on Twitter.
'Nah @justinbieber is miming at V Fest. I ain't paid £80 for a ticket to his tour to listen to his CD and see him run around the stage,' a fourth tweeted.
Strangely, Justin praised UK audiences for being authentic before revealing that he was feeling slightly 'hungover,' according to The Sun.
Justin had spent the night before the gig partying with Rihanna at Tape nightclub in London.
'I'm a little hungover, I'm not gonna lie,' Justin told the crowd. 'You guys don't like to fake anything in the UK, which I respect.'