Troye Sivan surprised lucky fans at Radio City Music Hall on Tuesday night (October 9) with the debut of his Boy Erased song "Revelation."

The unreleased track, a hard-earned collaboration between Sivan and Sigur Rós's Jónsi, is featured in Joel Edgerton's forthcoming gay conversion therapy drama starring Lucas Hedges. The film follows a teen struggling to accept his sexual identity in a small Baptist community. Sivan also appears in the film in a supporting role, playing a young man who is enrolled in the same ex-gay program as Jared (Hedges).

After booking the role, the South Africa-born singer was eager to share his entire catalog with Edgerton in the hope that his songs would be featured in the film. In the end, two songs made the cut: Bloom's emotional breakup ballad "The Good Side" opens the film, while "Revelation" plays at a key moment of intimacy in Jared's journey, when he realizes that "this person who he's with is a revolution to him."

You can hear a snippet of the song in the trailer:

Sivan called the experience of working on this film — and the process of writing an original song for it — "inspiring" before launching into the airy ballad, accompanied by a string quartet. "I don't know if I'm allowed to sing it tonight. I hope it's OK," he joked.

"You're a revelation / Won't you liberate me now? / From my holy vow" he sings with raw honesty. "You're a revolution / I will liberate you now / As the walls come down."

The 23-year-old performer also opened up about his own coming-out journey to the sold-out crowd. During a moving performance of Blue Neighbourhood's "Heaven," Sivan stood in front of a glowing venue, illuminated by cell phones lights and camera flashes. He sang the final chorus of the queer track in front of a rainbow light display as fans proudly waved their own pride flags — a striking image that made the emotional onstage proposal that happened moments before all the more heartwarming.

Below, Sivan explains how he convinced Edgerton to use his music in Boy Erased: