Anne Heche's Final Performance in Girl in Room 13 Was 'a Tour de Force,' Says Elisabeth Röhm

Ryan Plummer/A+E Networks/Lifetime

Anne Heche takes one of her final bows this weekend in Lifetime's Girl in Room 13.

After the late actress died at age 53 last month, director Elisabeth Röhm tells PEOPLE she and Heche "were really proud of what we did," shedding light on human trafficking with the film, which premieres Saturday.

"It was a really positive experience working with her," says Röhm, 49. "These Lifetime movies move very quickly and they're a tough schedule, but she worked really, really hard, and she always brought her A-game, always elevated the other actors, was so generous to all the other actors."

RELATED: Anne Heche Was a 'Hero' for Victims of Violence, Says 'Girl in Room 13' Director Elisabeth Röhm

In Girl in Room 13, Heche plays Janie, the "heroic mother" of a recovering opioid addict (Larissa Dias) who is kidnapped by human traffickers. The movie follows Janie's determined fight to rescue her daughter.

"She was just a total pleasure, a hero for the film. She became a good friend and did a phenomenal job. Her performance is a tour de force, and it was really a privilege to direct her," adds Röhm.

Along with Dias, 29, Heche and Röhm participated in a PSA for a partnership between Lifetime, the Polaris Project and the National Human Trafficking Hotline. "What we really shared was a passion for the topic we were gonna tackle," she adds.

"Every single day we showed up to the project with a commitment to stop violence against women and to tell a tale that was dark and horrible, but with a fighting spirit and perseverance," says Röhm.

RELATED: One of Anne Heche's Last Directors Pays Tribute: She 'Held Nothing Back — in Life or in Performance'

Ryan Plummer/A+E Networks/Lifetime

Heche died last month after she spent a week in a coma following a fiery car crash into a Los Angeles home. Her family has since laid her to rest at Hollywood Forever Cemetery.

Röhm admits the reality of Heche's death is "very fresh, so we're all missing her and very shocked and devastated."

She continues, "I hope people celebrate her beautiful work and legacy. This film is a testament to her incredible passion for art and for humanity and for women and to create a mission, a movement, and to make a real difference in the world. So I couldn't speak more highly of her."

RELATED VIDEO: Anne Heche, Star of Another World and Men in Trees, Dies at 53

In addition to her upcoming movie What Remains, Heche also has a second memoir coming out posthumously. Available Jan. 24, Call Me Anne will be her follow-up to 2001's Call Me Crazy.

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Girl in Room 13 premieres Saturday at 8 p.m. ET on Lifetime.