The project will be executive produced by Jerry Bruckheimer and Michael Bay and written by 'Masters Of Sex' creator Michelle Ashford, reported Deadline.
Barr, 30, will play Julius Jackson, the lifelong best friend of Bobby (Michael Stahl-David) and now his loyal partner in crime.
Practical and straight-laced, Jackson got into the drug trade after returning from Vietnam and struggling to make ends meet - and now it is too late to get out.