Jul 22, 2011 11:10 GMT  ·  By

Security researchers warn that scammers are trying to trick Justin Bieber fans into signing up for premium rate services by making fake promises on Twitter.

With millions of fans around the world, most of them underage and easy to influence, Justin Bieber is constantly used as lure in scams and other attacks on social networking websites.

According to Graham Cluley, senior technology consultant at Sophos, one of these scams was recently spotted on Twitter targeting users who send messages to the pop star.

The scammers were monitoring mentions of @JustinBieber and were messaging the senders from rogue accounts suggesting they can get the singer as their follower if they participate in a quiz.

"Who knew that someone as famous as Justin Bieber could be one of your followers, u know. [LINK]," the rogue messages read.

Users who clicked on the link were taken to a page that claimed that solving a quiz would provide them with a password that unlocks the instructions to get followed by Justin Bieber.

The quiz also claimed there's an iPhone 4 that users can win if they provide their mobile operator and phone number. However, the fine print states that doing so represents their agreement to be charged £4.50 a week for a service they don't need.

"This scam is active right now on Twitter. I've told Twitter's security team about it, so hopefully they can shut it down - but it probably won't be long before a similar scam pops its head up taking advantage of the rich mine of users acting unsafely," the Sophos security expert warns.

Users should always be wary of contests or offers which ask them for their mobile phone numbers. People who have fallen for this trick should immediately contact their mobile operator and inform them that they don't agree to any additional services or charges.