Instagram 1 / 11

Independence Day sweethearts! Katy Perry celebrated the Fourth of July this year with her on-again, off-again boyfriend John Mayer. The "Firework" singer posted a photo on Instagram of herself and Mayer wearing matching patriotic outfits on Thursday.

PHOTOS: John Mayer's famous ex-girlfriends

In the adorable photo, Perry, 28, styles an American flag top, while Mayer, 35, sports a blue shirt with white stars. With their backs to the camera, they give each other a big hug. "Whose broad stripes and bright stars?!" Perry captioned the snapshot.

PHOTOS: Katy Perry and Russell Brand -- the way they were

An eyewitness tells Us Weekly that the pop superstar cheered on the "Paper Doll" singer while he performed at the Philly 4th of July Jam at Benjamin Franklin Parkway in Philadelphia. "She watched him perform [from] offstage and watched every second of his performance, singing along to every song and dancing," the source tells Us. "She was so into his performance and gave him a big hug and kiss when he finished afterwards."

"She seemed all about him," the insider added.

PHOTOS: Katy Perry's craziest style moments

In the July issue of Vogue, Perry opened up about her relationship with Mayer. The two were broken up at the time of her interview. "I was madly in love with him. I still am madly in love with him," she said. "All I can say about that relationship is that he's got a beautiful mind. Beautiful mind, tortured soul. I do have to figure out why I am attracted to these broken birds."


Best bikini Twitpics

Fashion don'ts

Best TMI tweets