David Meunier and Chris Sheffield have also boarded the David Duchovny drama.

NBC's Charles Manson drama is fleshing out its cast.

Awake alum Michaela McManus, Justified's David Meunier and The Last Ship's Chris Sheffield have boarded the series starring David Duchovny, The Hollywood Reporter has learned.

The 13-episode drama Aquarius, created by John McNamara (In Plain Sight), is set in the 1960s and stars Duchovny as Sam Hodiak, a Los Angeles police sergeant investigating a then-unknown Charles Manson. McNamara exec produces alongside Marty Adelstein, Becky Clements, Alexandra Cunningham, Jonas Pate, Melanie Greene and Duchovny, with Pate on board to direct.

PHOTOS Summer TV Preview

McManus will recur as Grace, Hodiak's ex-girlfriend and longtime family friend. She calls Hodiak in when her daughter, Emma, goes missing. Beside herself with worry, Grace is hoping that Hodiak can locate and return her "baby" to her, but she has no idea of the morass that Emma has sunken into.

Meunier will also recur as Roy, a menacing biker with a "personality to match." Manson's minion, not to mention his muscle, Roy backs his diminutive boss up violently when the occasion calls for it.

Sheffield, who next appears in MTV's Happyland, will play Hodiak's son.

They join a cast that includes Grey Damon, Emma Dumont and Gethin Anthony, who will play Manson.

McManus is repped by UTA and Principato Young; Meunier is with Resolution and Justice & Ponder; Sheffield is with Vince Cirrincione and Associates.

Email: Lesley.Goldberg@THR.com

Twitter: @Snoodit