New Kids on the Block & Backstreet Boys (NKOTBSB Tour) July 3, 2011

New Kids on the Block reunited in 2008 for the group's fifth studio set, "The Block," which marked its first release since 1994's "Face the Music."

The Backstreet Boys' most recent effort, "This Is Us," surfaced in 2009 and followed their 2007 release, "Unbreakable."

The two groups have sold more than 200 million albums combined, according to a press release.