One day after she introduced Mayer as her "boyfriend" to the cast of Broadway's A Christmas Story, the "Wide Awake" singer, 28, accompanied him to the concert at Newark's Prudential Center, where they both enjoyed and put on quite a show.
Arriving at the venue shortly before the event started, the couple held hands as they mingled with the band backstage, reported Us magazine.
While Mayer, 35, chatted up Keith Richards and Ron Wood, his pop star girlfriend smiled and laughed adoringly, a witness said.
A short time later, Perry -- in a black blazer, T-shirt, printed scarf, and black pants -- was escorted to the pit while her beau stayed behind to tune up his guitar.
After joining the band onstage to perform "Respectable," the star headed down to enjoy the rest of the concert with Perry.
"They rocked out. They were especially excited during 'Miss You' and 'Start Me Up,' but they were so into the whole show," an onlooker says of the pair, who've been going strong ever since reuniting in September after a brief separation.