The 23-year-old star unexpectedly revealed it during her interview with 97.5 NOW FM, reported Aceshowbiz.
"I've been in the studio at the moment already working on new stuff. I can't wait to celebrate 'Revival' but it's been fun to feel like I'm already moving towards other things, but 'Kill Em With Kindness' is lyrically my favorite song I put on the record and I definitely can't wait to be able for that to have a story," she said.
Produced by Benny Blanco and Rock Mafia, "Kill Em" follows up hits like "Good for You", "Same Old Love" and "Hands to Myself".
"Revival" debuted at No 1 on Billboard 200 following its release last year. Gomez has started working on her next studio installment, which she recently teased with a picture of her hitting the studio with the "Same Old Love" songwriter Ross Golan.