According to Deadline, Bennett will play Annabel Lee, the daughter of a powerful country music superstar (played by Mary Steenburgen).
The character is described as "a gorgeous country singer who is living in the shadow of her overprotective mother".
Grimes will reportedly play Eli Larkin, "a half-cowboy, half-modern guy who tries to get out of the crime ridden life he has grown accustomed to in order to help his siblings". However, the character finds that leaving his old life behind "is much harder than he expected".
The pilot - a family drama set against the backdrop of organised crime - will be directed by Michael Dinner, who previously helmed the pilot for FX series Justified.