50 Cent & Val Kilmer - Gun (poster)

According to 50 Cent, who has written three feature-film scripts recently, the role Kilmer will be playing was transported from a different screenplay. "He's actually a character from a different project, but I got him to come out of there when he saw the value of what he was looking for."

Fitty explained that "The Gun" has a "socially conscious" theme. "It's about how a weapon goes from manufacturing to its distribution point, to being in a citizen's custody — and how it ends up in the wrong hands," he said. "We watch the actual gun travel through a few different people's hands."

"I'm a criminal," explained Kilmer, saying he gets the gun at one point. "And we're friends."

"Gun" would mark the second time 50 Cent and Kilmer have collaborated, following their recent straight-to-DVD release "Streets of Blood." And if all goes well, the rapper said, perhaps 50 will ask the veteran actor to collaborate in the medium that made him famous.