While singing "Adore You" during her Bangerz Tour concert in Los Angeles on Saturday, Cyrus, dressed in a sparkling black cat suit and platform heels, came down from the stage and locked lips with Perry, who was sitting in the front row.
The kiss lasted just a second but seemed to catch Perry by surprise. She backed away quickly and put her hand over her mouth. Cyrus also seemed to gasp.
Perry Tweeted a photo of the aftermath and told Cyrus, "I adore you." Get it?
Check out video of the smooch and Perry's Tweet below: