Shelley Duvall hadn't performed on screen in more than 20 years before she signed on for what would become her final project, an indie horror film called The Forest Hills.

The iconic actress, who died Thursday at 75, initially signed on to make a cameo appearance in the movie, which follows a man named Rico (Chiko Mendez) who "is tormented by nightmarish visions after enduring head trauma while camping in the Catskill woods." Duvall stars as Rico's abusive mother. In an exclusive behind-the-scenes video, which you can watch below, the film's writer and director, Scott Goldberg, says Duvall's role expanded after she arrived on set.

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"Her character was first a cameo role, a Friday the 13th Pamela Voorhees type of flashback," the filmmaker says. "After that scene, she expressed interest in working with someone else on camera. Then being able to finally work with Shelley and be there in person, and actually film with her — she's kind, sweet, gentle, and such an amazing actress."

Duvall says in the video, "Working with Scott Goldberg was really exciting because we used a lot of new technologies [and] cameras, and I was amazed at how easy it became to become a filmmaker." She adds, "This kind of filmmaking is the future: smaller, more intimate crew that at any time can be increased per the script… and the lighting and all that takes so much less time."

Best known for starring opposite Jack Nicholson in The Shining, Duvall announced her retirement from acting in 2002, after appearing in the comedy Manna from Heaven. In 2016, she reappeared on a controversial episode of Dr. Phil's talk show, where she revealed she'd been suffering from mental illness. The interview drew ire from fans, who knocked Dr. Phil for "showboating the visibly ill." Vivian Kubrick, the daughter of Shining director Stanley Kubrick, was also among the interview's critics, calling the show out for a lack of "compassionate healing."

Duvall died in her sleep at her home in Blanco, Texas, her partner, Dan Gilroy, confirmed to Entertainment Weekly.

In an email to EW, Goldberg said, "Shelley was an amazing actress to work with, and I will forever be grateful for the opportunity to direct her. She will be missed."

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The filmmaker added that Duvall "leaves behind an amazing legacy and will be missed by so many people, myself included. I am proud of her for overcoming adversity to act again and will always be forever grateful for her friendship and kindness."

Duvall previously won the Cannes Film Festival Best Actress honor for 3 Women and later won a Peabody Award for her beloved Faerie Tale Theatre series. She was also nominated for two Emmys, one BAFTA, and countless other honors throughout her career.

In addition to Gilroy, she is survived by brothers Scott, Stewart, and Shane.

The Forest Hills, also starring Edward Furlong and Dee Wallace, does not yet have a release date.