When We Rise: Pauley Perrette, T.R. Knight to guest-star

LGBT rights mini-series When We Rise has added another batch of guest stars to its roster, EW has confirmed.

Pauley Perrette (NCIS), T.R. Knight (Grey’s Anatomy), and Mary McCormack (The West Wing) have all signed on to the ABC project for undisclosed roles. Also set to appear are Rob Reiner (New Girl), Phylicia Rashad (The Cosby Show), Richard Schiff (House of Lies), Arliss Howard (True Blood), Henry Czerny (Revenge), and William Sadler (Hawaii Five-0).

The newly announced lineup joins recurring cast Guy Pearce, Mary-Louise Parker, Rachel Griffiths, Michael K. Williams and Ivory Aquino, plus previously announced guest stars Whoopi Goldberg, Rosie O’Donnell, Denis O’Hare, and David Hyde Pierce.

Helmed by Academy Award-winning screenwriter Dustin Lance Black (Milk), When We Rise chronicles the personal and political turmoil and triumphs of an LGBT group who helped pioneer one of the last legs of the U.S. Civil Rights movement. The period drama spans the LGBT movement from the 1969 Stone Wall Riots to present day.

Pearce portrays LGBT activist Cleve Jones, while Parker takes on women’s rights leader Roma Guy, and Griffiths will play Guy’s wife, social justice activist Diane.

Goldberg’s part tackles Pat Norman, the first openly gay employee of the San Francisco Health Department; O’Donnell depicts Del Martin, co-founder of the first lesbian organization in the country; and Denis O’Hare will play Foster, an openly gay Democratic party organizer.

The 7-episode series is executive produced by Black, Laurence Mark, Bruce Cohen, and Gus Van Sant, with Van Sant on board to direct the two-hour premiere.

When We Rise wrapped shooting Wednesday in Vancouver.

Variety originally reported the news.