Justin Bieber may want to leave the circus to Britney Spears from now on.
After writing excitedly about his "big night ahead" just hours ago, the newly 19-year-old star just dejectedly tweeted, "Worst birthday."
An eyewitness source exclusively tells E! News that Bieber did indeed hold a circus-themed birthday bash at London's Cirque du Soir tonight with guests including British singer (and the teen's new rumored flame) Ella-Paige Roberts Clarke.
But a couple of hours ago, the insider says, a confrontation occurred between Bieber's entourage and club security, prompting Bieber's entire party to leave. The entire incident went down very quickly and they headed straight back to their hotel afterward, the source adds.
Twitter, meanwhile, is abuzz with disappointed fans using the hashtag "#BeliebersHatePaparazzi" and blaming photographers for ruining the Biebs' big day.