Gil Bellows and Austin Nichols have rounded out the cast of Open Road’s JFK assassination pic “Parkland.”

The ensembler already stars Paul Giamatti, Billy Bob Thorton, Zac Efron and Marcia Gay Harden, with Peter Landesman directing.

Playtone partners Tom Hanks and Gary Goetzman will produce along with Exclusive Media toppers Nigel Sinclair and Guy East also producing.

Best known for his roles in “The Shawshank Redemption” and “Ally McBeal,” the Innovative Artists- and Medavoy Management-repped Bellows has most recently been seen in the CBS skein “Vegas” and Starz series “Boss.” The UTA-repped Nichols was most recently on Fox series “The Mob Doctor.”Allen is repped by APA and Konrad Leh of Creative Talent Group.