Justin Bieber has 'Worst birthday' in London

Justin Bieber’s 19th birthday didn’t turn out the way he had hoped.

The singer, who turned 19 on Friday, celebrated his birthday with a circus-themed party at London's Cirque du Soir Friday night, where a confrontation between Bieber’s security and the venue’s security caused the night to go downhill. An insider told Us Weekly that 14-year-old Jaden Smith, Will Smith’s son, accompanied Bieber to the club where he was denied entrance because of his age.

"There was never any mention of Jaden being there, so when he showed up, it caused problems," the insider told Us Weekly. “They could have stayed if Jaden left, but Justin wanted to be loyal to his good friend."

After Smith was unable to enter the club, Bieber and his posse immediately left the scene and headed back to the hotel, an insider told E! News. The singer took to Twitter complaining about the ruined night tweeting “Worst birthday.” This tweet come just hours after the "Boyfriend" singer tweeted earlier in the day that it was "gonna be a fun day."

Worst birthday

— Justin Bieber (@justinbieber) March 2, 2013