During an appearance Thursday on The Late Show with Stephen Colbert, out singer-actor Troye Sivan talked about his upcoming film Boy Erased.

Based on Garrard Conley's 2016 book Boy Erased: A Memoir of Identity, Faith and Family, Boy Erased stars Lucas Hedges as Jared, a college student who is sent to an “ex-gay” camp after he is outed to his conservative parents, played in the film by Nicole Kidman and Russell Crow. The film opens on November 2.

(Related: Garrard Conley: You don't have to be in conversion therapy to be in conversion therapy.)

Sivan, who plays Gary in the film, told Colbert that filming the movie reminded him of his own coming out.

“I remember being so relieved when I came out to myself because I was like, okay, this is not something that I can change. It's not something that I have to fight anymore,” Sivan said, adding that young people in “ex-gay” camps are told, “No, this is not you, you weren't born like this. This is a God-shaped hole you are trying to fill with these homosexual tendencies.”

“And, imagining being 15 again when I was sort of at my most vulnerable and having that put back on me, and being set up with that impossible task of trying to change this thing that ultimately is unchangeable – it's just one of the most damaging things I can imagine.”

Sivan added that he hopes the film speaks to parents about how their reaction to their kids coming out “can really shape their lives.”

Boy Erased opens on November 2.

(Related: Ariana Grande, Antoni Porowski, Tyler Oakley celebrate release of Troye Sivan's Bloom.)