Back in the studio era, recording stars routinely made movies, and actors and actresses often recorded records. Everything was vertically integrated, so it made sense to use cult of personality to move as many different types of units as possible. That changed for awhile, as the studio system crumbled, and the 70s renaissance of American film coincided with a bleak overall period for American popular culture. But now it seems like things are coming full circle. Gwen Stefani doesn't make a near-mute appearance in The Aviator because anyone imagines that she's got an acting talent that needs to be shared with the world – she takes the role of Jean Harlow, which probably could and should have been larger, because it cements her status as a Great Blonde, which is in itself a fab commercial for her solo record and fashion line. And ordinarily, no one would expect Get Rich or Die Tryin', otherwise known as The 50 Cent Movie, to be anything more than a 2-hour commercial for that rapper and his very specific, bullet-riddled mythology. 50 might go on to play characters not based on himself, in other films or TV shows that are not based on his life, but I sort of doubt it. More than likely, that's not really the point here. I don't think Die Tryin' wants to be a memorable moment in moviegoing; I'm fairly sure that it will settle for being a successful moment in marketing, and anything else is gravy.
But then why did they need Jim Sheridan – a six-time Oscar nominee for In the Name of the Father and In America, and other films about Irish people – to direct it?