Lily Collins said Ted Bundy’s ex-fiancée was a “positive light” on the set of the new film about the serial killer.

Collins, who portrays Bundy’s former fiancée Elizabeth “Liz” Kloepfer in “Extremely Wicked, Shockingly Evil and Vile,” told the hosts of the British morning show “This Morning” she was able to meet Kloepfer to prepare for her role.

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“It was really helpful,” Collins, 30, said Tuesday. “And she was so gracious, her and her daughter Molly were so gracious, and inviting me and giving me material to look at and speaking to me and just allowing me to ask questions.”

Though Collins said she wasn’t sure if Kloepfer would actually see the film because of how difficult the story is, she was still supportive while they were working on the project.

“Within the filming process she came and visited set and was just such a positive light on set, which I don’t know if one would expect her to be necessarily with what happened,” Collins said.

“She’s so lovely and she gave us her support,” she added.

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Last week, Zac Efron, who portrays Bundy in the film, told reporters he struggled to separate himself from his character.

“I’ve never played a role in which I really have to separate myself from when I go home at night and it was almost impossible. I’d like to say that I did it successfully but I couldn’t,” Efron said on the red carpet of the London premiere of the film, according to the Daily Mail.

Lily Collins, who portrays Ted Bundy's longtime girlfriend and ex-fiancée Elizabeth “Liz” Kloepfer in “Extremely Wicked, Shockingly Evil and Vile” said she met the real Kloepfer, who was "gracious" and a "positive light" on the set of the film. (Reuters)

“I really wasn’t interested in playing a serial killer. I’m not in the business of glamorizing a horrendous person or his acts, but there is something unique about the way we went into the psyche of Ted, and his longtime girlfriend Liz,” he added.

Bundy was convicted of killing three women and confessed to murdering more than 30 others across the U.S. in the 1970s before his execution by electric chair in January 1989.

“Extremely Wicked, Shockingly Evil and Vile” is a biopic about Bundy’s life and is told from the perspective of his longtime girlfriend and fiancée Kloepfer. It is set to be released on May 3.