Watch Jessica Chastain's shocking facial transformation on The Eyes of Tammy Faye set

EW has an exclusive sneak peek at the hours of makeup and prosthetic work Chastain underwent to become Tammy Faye in the Oscar-buzzed biopic.

Jessica Chastain's performance in The Eyes of Tammy Faye is an Oscar-worthy godsend, but she had to undergo a hellish makeup routine to get to the heart and soul of the titular televangelist.

An exclusive clip from the biopic's home-release bonus features (above) teases Chastain's jaw-dropping transformation into the religious icon, who endured a wealth of scandals — including several stemming from her husband, televangelist Jim Bakker (Andrew Garfield). The Academy Award-nominated actress underwent hours of prosthetic work to recreate Bakker's appearance across three distinct phases of her life.

"I wanted to look as much as I could like her so I could... feel different. I don't know that I could've done the character without it," Chastain says in the preview, as shots flash onscreen showing her sitting in a makeup chair while professionals apply various pieces to her face. "I don't know how to separate the two; the prosthetics were her, in some aspect."

Justin Raleigh, the film's Emmy-nominated prosthetic makeup designer, describes each phase of Bakker's life as a new "prosthetic milestone," which involved increasing the number of cheek pieces, adding volume around her chin, applying a full neck section, and creating creases and wrinkles atop it all.

"The physical cost of doing this role is so tremendous because she is encased in latex, wigs, trusses, pregnancy pads, nails out to here," continues Cherry Jones, who plays Bakker's mother in the film. "I don't even know how to describe what it must feel like."

Chastain's army of aesthetic magicians — including Raleigh — previously detailed the intensive process of making the actress over for the part in a series of interviews with EW: "Jessica has more of an angular face, and Tammy had a much fuller, rounder face," Raleigh said, further explaining that he used 3-D modeling and traditional casting to make the prosthetic additions that took almost two and a half hours to set on Chastain's body. The key pieces, he continued, were "cheek appliances that would widen her face" as well as a "prosthetic to fill in the dimple in her chin."

The Eyes of Tammy Faye, directed by Michael Showalter, is now available on digital platforms ahead of its Nov. 16 release on Blu-ray and DVD. Watch EW's exclusive clip from the release's special features above, and keep track of Chastain's place in the hunt for Academy Awards here.