Thora Birch and her magnificent breasts are set to replace human drug Lindsay Lohan in Junction Films’ upcoming bio-pic Manson Girls. The 28-year-old American Beauty starlet will play Nancy Pitman, a Charles Manson cult follower who later served time for her involvement in a deadly Aryan Brotherhood murder.

Manson Girls is directed by Susanna Lo and costars Heather Matarazzo (Hostel II), Jennifer Landon (“As the World Turns”), Erin Kelly, Michael Monks and the very fat Nikki Blonsky (“Huge”). Production on the movie begins on Feb. 2011.

Birch was nominated for a Golden Globe award for her performance in the 2001 dramedy Ghost World. Since then, she has been slumming it in the straight-to-DVD market, appearing in Dark Corners, Train and the Brittany Murphy vehicle Deadline.

(UPDATE: THORA HAS DROPPED OUT OF THE MOVIE. MOST LIKELY BECAUSE OF THIS)