Playing the Joker onscreen means stepping into some big shoes left by Jack Nicholson and Heath Ledger. So how is Jared Leto preparing for his role as the iconic Batman villain in Suicide Squad? By getting bigger.

"Do you mind if I eat a little?" Jared Leto asks Billboard during an interview for our new cover story, out Friday, Feb. 20. "I'm trying to gain a lot of weight. It means I have to eat every couple of hours -- and I'm terrible at eating a lot." (Case in point: Leto was eating vegan tacos during the interview, which are hardly the fattiest food on the market.)

Jared Leto to Play the Joker in Upcoming Film 'Suicide Squad'

Last December, Warner Bros. announced Leto would take on the Batman bad guy in a movie starring DC Comics supervillains. And he's not the only A-lister in the film: Will Smith also stars as Deadshot.

The 30 Seconds to Mars frontman, who won an Oscar for his portrayal of the transgender Rayon in Dallas Buyers Club, explains the increasing complexity of graphic novels drew him to this project.

"The opportunity to take on this nearly Shakespearean character -- that's what graphic novels and comic books are becoming, right?" Leto says. "[He's] this beautiful disaster of a character -- what a big challenge."

Read Billboard's full cover story about Jared Leto -- and fellow musician-actors including Jennifer Hudson and Jack Black -- on Friday, Feb. 20.