Trending: The all-singing, all-dancing, all-filming stars

Box office draws: Katy Perry (left), Beyoncé (centre) and Justin Bieber (right) (Reuters/Getty Images)

Nothing says global pop star right now like appearing on the big screen in a documentary about your life: your music, your relationships, your family, your tantrums, your tears. It's a narcissist's dream. Now Beyoncé is said to be directing, producing and appearing in a film that will include concert footage, backstage scenes and interviews with her and her loved ones. Clearly her day job of singing, designing and acting wasn't fulfilling enough.

So far, the recent spate of popstar documentaries has been aimed squarely at the tween market: Miley Cyrus, the Jonas Brothers and Justin Bieber have all released behind-the-scenes movies (One Direction have a film in the pipeline, too). But would a pop star whose audience didn't consist solely of nine-year-old girls still manage to be a draw at the box office? Katy Perry certainly thought her fans would be happy to fork out the price of a cinema ticket to see what was billed as a warts-and-all portrayal (signed off by her, naturally). And they were; her film Katy Perry: Part of Me has earned $30m at the box office so far. That, however, pales in comparison to the $100m Justin Bieber's Never Say Never brought in.

Not only do these pictures make a handsome profit but they can be a brilliant way to broaden a star's appeal by carefully manipulating the audience. I even know someone who came away from Never Say Never (I know) waxing lyrical about what a sweet boy the Bieb was. And we all know that's not true.