Canadian superstar Justin Bieber has spoken out about his birthday debacle, claiming "aggressive dummies" ruined his night.

The 'Baby' hitmaker took to Twitter over the weekend to let his fans know he'd had the "worst birthday".

The marketing and PR director at London hotspot Cirque Du Soir explained that Bieber's birthday night came to an abrupt end because of a couple of underage members of his party - Jaden Smith, 14 and  Ella-Paige Roberts Clarke, 17.

However, Bieber has rubbished such claims, explaining the club's staff were rude.

Writing on his Instagram account, the star revealed: "The funny moment when people believe I brought underage people to a club... You think Will [Smith] is letting his 14 year old [son Jaden] in a club, I don't think so.

He added: "I love how the club wanted to give the press another reason to why we didn't stay at their weak a** club so they wouldn't look bad for me walking in and right back out.

"I said 'worst bday' [on Twitter] but that was due to dummies pushing over my fans and being overly aggressive... it wasn't the worst bday cuz all my friends from back home flew in... I was just mad in the moment."

Bieber then took to Twitter to explain speaking out on the incident: "Sometimes you just wanna vent and not be quiet. I love my fans though. Just gonna chill with friends. London shows this week. It ain't always easy but is what it is. Gonna stay focused (sic)." Watch Justin Bieber's 'Right Here' lyric video below: