Baby-faced Anton Yelchin—who's earning major buzz for his performance in Like Crazy—has the floppy hair and the chops to play a young Robert Mapplethorpe.
Patti Smith is an icon with a unique look—which makes it difficult to come up with an actress who could convincingly portray her teenaged self onscreen. That being said, we think whip-smart Olivia Thirlby of Juno might be a good fit, even if she's a little too traditionally beautiful for the role.
Future Pulitzer Prize-winner Sam Shepard, who Smith called "rugged, smart, and intuitive," was romantically and professionally involved with the singer in the '70s. We like square-jawed Max Irons (son of Jeremy) as the playwright's younger self.
Billy Crudup would do a nice job as Sam Wagstaff, the curator and art collector who served as Mapplethorpe's mentor and, eventually, his lifetime companion.
One of Just Kids's most memorable passages involves Allen Ginsberg buying Patti Smith dinner—then, later, telling her he only did it because he had mistaken her for "a very pretty boy." David Cross has played Ginsberg before (in 2007's I'm Not There), but he's such a dead ringer for the poet that we can't resist casting him again.
Harry Potter alum James Phelps bears a striking resemblence to Lenny Kaye, Smith's longtime bandmate. And if he's not up for the task, the producers of Just Kids could always look to his twin brother Oliver instead.