Robert Rodriguez and Frank Miller have brought in Oscar-winning screenwriter William Monahan (The Departed) to work on the script for Sin City 2, reports Heat Vision. He'll be working from a draft completed recently by Miller.
Earlier this month, Rodriguez said that filming could start as early as later this year.
"'Sin City 2' is going good, we're just finishing the script for that, we already got the money. We have everything we need so we can just start shooting as soon as we get the pages," he said.
It is unclear which actors might return for the next film, though the previously-rumored "A Dame to Kill For" storyline again features Marv (Mickey Rourke) and Nancy (Jessica Alba).
Released in April of 2005, Sin City earned $158.8 million worldwide. The graphic novel adaptation was made for just $40 million, not counting marketing costs.