Good Charlotte just had a reunion performance and Cameron Diaz was there to cheer on husband Benji Madden as Jessie J, the guitarist's co-mentor in "The Voice Australia," also bonded with the "Sex Tape" actress.

"Jessie and the Charlie's Angels actress laughed incessantly as they watched the show from a separate balcony, which was also occupied by Cameron's sister-in-law Nicole Richie, who is married to front-man Joel Madden," said Daily Mail.

The Good Charlotte reunion show at the Troubadour in Los Angeles was a success as the tickets were sold out within minutes. The band disbanded last year after twins Joel and Benji formed their own band, The Madden Brothers.

"The pop-punk band have teamed up with Alternative Press to announce a one-night-only reunion gig," Fuse TV reported. "GC will perform at the Troubadour in Los Angeles, California, on Thursday, November 19."

During the reunion performance, Benji Madden and Joel Madden also dropped a new track, "Makeshift Love," which might be part of their new album.

Alternative Press commented, "At the Troubadour, they played all of their early hits. They opened with 'The Anthem' and closed with 'Lifestyles Of The Rich And The Famous' and just like they did in the early '00s, those songs sounded like the work of a scientist who went into a lab with some plutonium, the mid-'90s Fat Wreck Chords catalog and a case of Manic Panic hair dye, only to come out with the most perfectly engineered pop-punk band alive."

Nevertheless, Cameron Diaz proved that she's Benji Madden's biggest fan.

According to Daily Mail, Cameron Diaz was singing along to some of the songs performed by husband Benji Madden and the rest of the Good Charlotte band.

"Dressed comfortably for an evening of non-stop dancing, the 43-year-old star sported a camouflage print shirt and ripped jeans," the article said.

Cameron Diaz and husband Joel Madden tied the knot at her Beverly Hills mansion in January this year.