Just more than two years ago, Cynthia Nabozny—the now-24-year-old singer and songwriter who records under Cyn—wrote a song with the producer Felix Snow that began as a guitar-based melody. “I was like, ‘Wow, it reminds me of John Mayer vibes,’” Cyn said recently. But Snow wasn't satisfied.

“He was like, ‘I want to try something,’” she recalled. He gave it a quick, electronic touch-up: “Five seconds later, it was completely different,” she said. At that point, Cyn had yet to move to Los Angeles, yet to meet Katy Perry, yet sign to her imprint Unsub. Now, two years later, “Only With You,” the song that led to all of the above, premieres exclusively here on W.

Only With You” begins with a menacing bass thrum and a funky guitar line as Cyn sings of stars and matter and space, taking a meditative tone (she had just read Lucretius’s On the Nature of Things at the time). But with a drop of the bass and a vault into falsetto, the song transforms into a declaration of loyalty directed at an unnamed “you”: “I don’t want anything to do with anyone but you,” she sings, “only with you.” “Only With You,” it turns out, is a heady mix of ancient philosophy and contemporary romance drawn from Cyn’s relationship status at the time. “It was time to take it to that next step,” she said.

Just a month or two after she wrote “Only With You,” in September 2015, Cyn met Perry in Los Angeles. She sat down at the piano to play a song, and, as far as she can recall, “Only With You” was the one that came out. “That was scary,” she recalled emphatically.

The song "really encouraged Katy and the rest of her team to look at me as a solid investment,” Cyn said. “It’s definitely one of those songs that took me into my next level.” The meeting “changed my life,” she added—a few months later, she became just the second signee of Perry’s Unsub Records. By the end of the year, she had relocated to Los Angeles.

Still, at that point, she hadn’t yet written enough to compose an album, so she lived with “Only With You”—continuing to listen to it and play it for friends—for another two years before it was finally tapped to be released as a single. “It feels like, finally, I can show it,” she said. Plus, now she has a whole EP’s worth of material, of which “Only With You” is just a first sampling.

Katy Perry admits she cries to some of her own songs: