Nic Pizzolatto and Robert Downey Jr. are in talks for a drama project, with the “True Detective” creator attached to write and the “Iron Man” actor attached to star, sources tell Variety.

HBO and reps for both Pizzolatto and Downey Jr. declined to comment.

Plot details are scarce, but insiders say the project is based on Downey Jr.’s “Perry Mason” reboot, which he had been developing as a feature film at Warner Bros. for several years. Pizzolatto, Joe Horacek, Downey Jr., and his producing partner and wife, Susan Downey, of Team Downey will serve as exec producers.