(Cover) - EN Showbiz - Justin Bieber was left feeling vulnerable after two overzealous fans sneaked into his hotel suite.

The Canadian pop sensation was discovered in 2008, but achieved worldwide success last year when he released his single Baby in January. Global success and a hoard of teenage fans quickly followed. The 17-year-old singer is constantly inundated with over-enthusiastic fans and has even had to postpone shows before because of safety fears.

The most recent incident left the singer worried after two teenage girls, aged 16 and 18, sneaked into his 750-a-night suite disguised as cleaners.

The hotel was swamped by fans all desperate to catch a glimpse of Justin. But two particularly enterprising girls snuck in through a side entrance, and stole two housekeeping outfits, a source told The Mirror. After ditching their regular clothes and slipping into their new costumes, they got the lift to Justins suite and knocked on the door, calling, Housekeeping.

The Canadian star who is currently touring in Liverpool, England has previously expressed his gratitude, and says he truly appreciates his young beliebers the nickname given to his fans. However, the two teenage girls took advantage of the situation and began taking pictures of the stars belongings, leaving Justin feeling vulnerable and so he decided to sleep in his tour bus overnight.

No one clocked on until the girls were alone, and in his bedroom, taking pictures of his personal possessions on their phones. A member of Justins entourage in another part of the suite heard them giggling and came through, catching them in the act, the source added. The girls, following a telling-off, were evicted from the premises.

The star has previously stated he owes a lot to internet social networking sites Twitter and Facebook. His meteoric rise to stardom began to take off when he accessed the sites in order to communicate with fans. (C) Cover Media