Justin Bieber is at the centre of a state investigation in Texas amid allegations the superstar was drinking alcohol illegally at a club on Friday night (18Oct13). The Baby hitmaker, 19, was said to be drinking water while partying with pals at NOX Houston, but photos have since surfaced showing the singer holding an open bottle of Dos Equis beer inside the venue. An official complaint has been filed with the Texas Alcoholic Beverage Commission and an investigation has now been launched, according to TMZ.com. If authorities rule that Bieber was illegally served booze in the club, bar bosses face a hefty fine and could have their liquor licence revoked. The legal drinking age in the U.S. is 21. However, the singer himself won't face any legal issues as he was not caught in the act. Bieber had an eventful Friday night out - he was also spotted at the VLive gentlemen's club, where he reportedly left a stripper starstruck by grabbing her backside.