During their concert in Virginia Beach, Va. on Friday, Aug. 15, Nick Jonas, Joe Jonas and Kevin Jonas brought out Hanson, surprising fans with a performance of their 1997 hit "MMMBop." Hanson, made up of brothers Isaac, Taylor and Zac, took the stage at the Veterans United Home Loans Amphitheater with an extra layer of nostalgia.

Parade. The Jonas Brothers are only four dates into their JONAS20 Tour, but they keep upping the ante when it comes to surprise guests. As if the performances weren't enough — and they were, as the band-of-brothers crossover instantly had pop fans in a chokehold — both bands actually acted out the lyrics backstage.