T.R. Knight is set to star in the upcoming Donmar Warehouse production of the Alfred Uhry-penned musical “Parade,” opening Oct. 4 at L.A.’s Mark Taper Forum.Knight, who just ankled ABC’s hit skein “Grey’s Anatomy,” will play Leo Frank alongside Lara Pulver as his wife, Lucille. Michael Berresse, Charlotte d’Amboise and Tony winner Christian Hoff are all set to co-star. Pulver received an Olivier kudos nod for her London portrayal of Lucille. Previews start Sept. 24 with perfs running through Nov. 15.