Back in 2024, the Los Angeles Times referred to Taylor Swift as “patient zero for emotional contagion,” which may have inspired her lyrics from this single off Life of a Showgirl: The Encore, set to release on Sept. 25, 2026.

However, “Patient Zero”—which features Dakota Johnson and Colin Farrell in the music video—explores Taylor’s connection with a woman over a shared ex, starting with, “If you wanna party with somebody who might know / About the devil on his shoulder under his halo / When the toxins take their hold, you’d rather die than let it go / But if you’re sick of him, I got you, I was patient zero.”

If an ex having a halo (or lack thereof) sounds familiar, she also touched on that theme in “I Can Fix Him (No Really I Can)” from Tortured Poets, which seemingly alluded to her ex Matty Healy. Taylor sang at the time, “He had a halo of the highest grade/ He just hadn’t met me yet.”

Now that Taylor is happily married, she is sharing insights with her ex’s new partner in “Patient Zero.”

“Take it from somebody who lost his games but won the race / Take it from someone who said all of this to his face,” she expresses. “Someone who knows she’s more than just the chase / Someone who had him and walked away.”

So, who could she be singing about? It might have been inspired by her girls’ night out with Sophie Turner shortly after the actress’ 2023 split with Joe Jonas, whom Taylor dated in 2008. (He is also believed to have inspired Fearless‘ “Forever & Always” and “Mr. Perfectly Fine.”)