Justin Bieber Thanks Fans After 'Worst Birthday'

Justin Bieber performs at KIIS FM's Jingle Ball 2012 night 2 at Nokia Theatre LA Live on December 3, 2012 in Los Angeles, California.

Justin Bieber started off his 19th birthday yesterday (March 1) tweeting happily about his "big night ahead," but by the wee hours, he'd tweeted it had turned into his "Worst birthday." The teen singer reportedly cut short his circus-themed birthday bash at London's Cirque du Soir after a disagreement with security about whether some of his pals were too young to enter the club, according to Us Weekly and E! Online.

Friend and collaborator, actor Jaden Smith, who is 14, was reportedly among the invited guests seeking entrance. Rather than see his buddy turned away, Justin and his fellow partygoers are said to have left the London club quickly, with Bieber soon returning to his hotel.

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The newly 19-year-old Bieber, who is in the midst of a string of U.K. concert dates, and who recently had his fifth No. 1 album on the Billboard 200 with "Believe Acoustic," quickly bounced back from his birthday bummer. In the day following his 'worst' tweet, Justin was back on Twitter after a Nottingham, England gig thanking his fans, saying "I see and saw all the posts from around the world. U got me smiling. Love u. Thank u."

Soon after, Bieber also retweeted an encouraging message from his manager Scooter Braun, who wrote "Life is a roller coaster. Just know when u dip low it is only to build excitement as u will fly high again. Enjoy the journey."

Justin spent over an hour thereafter retweeting messages of support from fans. The hashtag #OperationMakeBieberSmile became a worldwide trend on Twitter on Saturday.

Bieber begins a run of dates at London's 02 Arena on Monday, March 4.