An insider told Us Weekly Katy is not handling the break up well. "She is making it seem like it wasn't serious with John, but she is hurt."
On August 4, the "Firework" singer and Mayer were spotted at a Beverly Hills pool party together, not holding back any affection. They "were all over each other, making out," one observer said.
According to People magazine, a source said the pair "were honestly having fun. People made it out to be far more than what it was."
Perry recently divorced actor Russell Brand, and briefly dated Florence + the Machine rocker Robert Ackroyd in the spring. Mayer's ex line-up includes: Jennifer Love Hewitt, Jessica Simpson, Jennifer Aniston, Taylor Swift and more.
Singer Katy Perry and musician John Mayer, who made their first public appearance together in June, are no longer an item.