Bieber Explains 'Worst Birthday' Tweet

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After Justin Bieber's London birthday bash was cut short over the weekend, the pop star has posted a message to his Instagram account, voicing his side of the story.

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"The funny moment when people believe I brought underage people to a club.. U think Will [Smith] is letting his 14-year-old [son Jaden] in a club? I don't think so," wrote the 19-year-old singer, who had planned for a night at London's Cirque du Soir. "2nd I love how the club wanted to give the press another reason to why we didn't stay at their weak ass club so they wouldn't look bad for me walking in and right back out..i said 'worst bday,' but that was due to dummies pushing over my fans and being overly aggressive. Btw it wasn't the worst bday, cuz all my friends from back home flew in. I was just mad in the moment."

Previously, a source told Us Weekly that Jaden Smith's presence at the venue had been the catalyst for the disagreement. Bieber tweeted two words following the alleged altercation: "Worst birthday," which was shared more than 130,000 times.

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Beliebers immediately tweeted a flood of encouraging messages to which, Bieber responded by tweeting, "I see and say all the posts from around the world. U got me smiling. Love u. Thank u."

The next day, Bieber -- in a happier mood -- was spotted leaving the Mint Leaf restaurant in London.