A quiet date at the movies turned unexpectedly unpleasant this weekend for Canadian teen idol Justin Bieber and his girlfriend, Selena Gomez.

The 18-year-old pop star from Stratford, Ont. is wanted for questioning today by Los Angeles County Sheriff's investigators after a photographer accused the singer of "roughing him up."

The alleged altercation took place on Sunday outside the California shopping centre, The Commons, in the affluent L.A. suburb of Calabasas where the singer just purchased a 10,000 square-foot mansion.

According to entertainment news site TMZ, Bieber and Gomez were walking out of a movie theatre when a paparazzo attempted to snap a picture of the couple.

"The paparazzo allegedly blocked their way," said etalk's Traci Melchor on CTV's News Channel Monday.

An altercation of some sort erupted between the star and the photographer, with Bieber losing his shoe and baseball hat in the alleged confrontation.

Bieber also lost his cool, according to witnesses on the scene.

"Witnesses were claiming that Selena was trying to calm him down," said Melchor.

The photographer in question called 911 after the alleged scuffle, complaining of chest pains. Bieber and Gomez left the scene before paramedics and deputies arrived.

The paparazzo has since filed a police report naming Bieber in a case of criminal battery.

Now investigators with the Los Angeles County Sheriff's Department want to question Bieber to get his side of the story.

Bieber's team has yet to issue a statement on this latest brush with the law.

The singer faced a huge scandal in 2011, when 20-year-old Mariah Yeater accused Bieber of making her pregnant. Bieber was cleared against those accusations.

The Twitterverse, however, has been quick to weigh in on Bieber's recent troubles with this disgruntled photog.

"Justin Bieber now wanted for questioning. Will INTERPOL issue a Red Notice?" tweeted @wikileaks.

Others were not so sympathetic to the injured party accusing Bieber of foul play.

"Justin Bieber being investigated for beating up a photographer. Why would anyone ever admit they were beaten up by Justin Bieber?" tweeted Dean Obeidallah (@Deanofcomedy).

Bieber may have been alluding to the event when he Tweeted a reminder to his fans overnight, about an upcoming single debuting on iTunes: "gonna focus on the important stuff. the music."

According to the star's Twitter feed, Bieber is travelling to Oslo Monday to promote his album, "Believe," which will be available in that country on June 19.