Pop singer Justin Bieber stunned Zac Efron by giving the actor advice on his career during a recent meeting.

The Sorry star and his friends dropped by Efron's Los Angeles home at the weekend (23Jul16), when Bieber decided to give him a few tips on how to handle his hot career, according to Us Weekly.

A source tells the publication the 23-year-old admitted he had been a fan since Zac's breakout film High School Musical, but suggested the Hollywood hunk should be "more selective about the roles he takes," adding, "Justin was very honest and kind of went in on Zac."

However, 28-year-old Efron, who just wrapped filming the new Baywatch remake, took Bieber's notes in stride and "appreciated" the advice, the insider says.

Efron reciprocated by giving him both praise and advice, with an insider saying Efron told him to "to keep breaking boundaries," adding, "He was giving him life tips."

Although he hasn't revealed plans to get serious about acting, Bieber's big screen performances have so far been restricted to his own concert films and minor cameos in films like Zoolander 2 and an uncredited part in Men In Black 3.

His representative recently shot down reports Bieber refused a role in one new movie unless a gay sex scene was cut out.

According to New York Post's Page Six, producers of Uber Girl allegedly approached him to play a young male pop star who has same a same sex romance with his backup dancer.

However Bieber's rep told GossipCop there's "no truth" to the story, adding talks about the star appearing in Uber Girl "never happened".