Talk about PDA!
The two appeared in matching Fourth of July ensembles and embraced in a big hug. Perry captioned the pic, "Whose broad stripes & bright stars?!"
The "Fireworks" singer wore an American flag-themed shirt with silver hoop earrings as she held onto her leading man, who wore a blue star print dress shirt and matching blue bandana.
Mayer was on hand in Philadelphia to perform for the Fourth of July Jam, one of the country's biggest music events for the holiday.
And with Perry by his side, it was apparent that Mayer was in good spirits.
Perry broke her silence about the singer and opened up about their hot-and-cold relationship in the latest issue of Vogue.
"It's over, I was madly in love with him. I still love him," she told the mag at the time. "Beautiful mind, tortured soul. I do have to figure out why I am attracted to the broken birds."
They two, who first began dating in August 2012, were on and off for a few months before rekindling their romance in early June 2013.
Two sources confirmed to E! News that the pair had reconciled and picked up where they left off. But according to a source, Mayer and Perry weren't interesting in jumping back into a serious relationship off the bat.
"They are just hanging out," the source explained. "They are not putting a label on it."
Perry also spilled the beans on her divorce from Russell Brand, saying, "He's a very smart man, a magical man and I was in love with him when I married him. Let's just say I haven't heard from him since he texted me saying he was divorcing me December 31, 2011."
She also hinted at possible reasons behind the split, "I have to claim my own responsibility in things. I do admit that I was on the road.
"I think a lot of times strong men do want an equal, but when they get that equal they're like, 'I can't handle it.'"